HEIDERN — FULL CHARACTER CARD

Information

Full Name: Heidern Japanese Name: ハイデルン Alias: General of the Soldiers of Fortune KOF XV Title: Hard-Boiled Assassin Gender: Male Birthday: September 1 Age: Not officially fixed across the different continuities Height: 192 cm (6'4") Weight: 90 kg (198 lbs.) Blood Type: B Birthplace: Unknown Faction: Ikari Warriors Occupation: Military Commander / Mercenary General / Military Strategist Affiliation: Ikari Warriors Mercenary Corps Fighting Style: Martial Arts + Self-Developed Assassination Techniques

Family:

• Leona Heidern — Adoptive Daughter.
• Sandra — Deceased Wife.
• Clara — Deceased Biological Daughter.

Notable Subordinates:

• Ralf Jones.
• Clark Still.
• Whip.
• Leona Heidern.

Character Appearances:

1. The King of Fighters — Original and modern appearances.
2. Metal Slug Defense — Heidern.
3. Metal Slug Attack — Heidern.
4. Metal Slug Attack — Special Heidern.
5. Metal Slug Awakening — Referenced through Leona's background and upbringing.

Voice Actors:

• Toshimitsu Arai — Earlier KOF appearances, including KOF '94 through KOF 2001 and associated versions.
• Haruo Yamagishi — KOF XIV and KOF XV.

Personality

Heidern is a cold, calculating, disciplined, and highly experienced military commander.

He possesses an extremely analytical mind and approaches military operations with precision. He rarely allows personal emotions to interfere with his responsibilities and is willing to make difficult decisions when the situation requires them.

His fighting style and military leadership reflect his experience as a soldier who has spent years confronting dangerous opponents.

Although he maintains a strict and intimidating exterior, Heidern is not entirely without emotion.

His most important emotional connection is his adoptive daughter, Leona.

Despite his normally cold demeanor, he demonstrates considerable paternal affection toward her. He is particularly protective of her because of the tragic circumstances surrounding her childhood.

He also values his subordinates, including Ralf, Clark, and Whip, and considers their welfare important.

Personality Traits:

• Cold and calculating.
• Extremely disciplined.
• Highly intelligent and strategic.
• Experienced military commander.
• Strict but dependable.
• Emotionally reserved.
• Protective toward his family.
• Respectful toward capable subordinates.
• Patient and observant.
• Determined to complete his missions.

Backstory and Lore

Heidern is the commander of the Ikari Warriors, a mercenary unit operating under his leadership.

His original life was destroyed by Rugal Bernstein, who attacked his military base, killed his wife and daughter, and deprived him of his right eye.

Following this tragedy, Heidern established his own mercenary organization and developed his personal assassination techniques.

He initially entered the King of Fighters tournament alongside Ralf Jones and Clark Still as the Brazil Team, later recognized as the Ikari Warriors.

During his military career, he encountered an orphaned, amnesiac girl named Leona, whom he eventually adopted as his daughter.

Rather than treating her as an ordinary soldier, Heidern raised her under strict military discipline and personally oversaw her development.

His relationship with Leona is one of the most important aspects of his character.

Across Metal Slug Defense and Metal Slug Attack, Heidern makes the transition into the Regular Army's universe as a crossover military commander.

In Metal Slug Attack, he participates in OPERATION IKARI and later appears in additional Extra Ops and character-related stories.

Metal Slug Awakening also establishes his influence on Leona's upbringing, describing him as the mercenary instructor who adopted her and raised her through strict military training.

Full Appearance

Heidern is a tall, muscular, middle-aged man with short, dark hair, a stern facial expression, and a distinctive black eyepatch covering his right eye.

His remaining eye is sharply focused, reflecting his disciplined and observant personality.

His military clothing varies between the classic KOF design and his updated tactical appearance.

Classic KOF Appearance

Head and Face:

• Short, dark hair.
• Black eyepatch covering his right eye.
• Stern facial expression.
• Strong facial structure.
• Dark military beret with an insignia.

Upper Body:

• Olive-green military uniform.
• Long-sleeved military jacket.
• Reinforced shoulder sections.
• Military insignia and shoulder markings.
• Dark undershirt.
• Tactical gloves.

Lower Body:

• Matching olive-green military trousers.
• Military belt with prominent buckle.
• Reinforced trousers suitable for field operations.
• Dark military boots.

This is the recognizable classic appearance associated with his earlier King of Fighters illustrations.

Modern KOF XIV / KOF XV Appearance

His later appearances introduce a more modern tactical design.

Head:

• Dark-blue military beret with a gold insignia.
• Black right-eye eyepatch.
• Short dark hair.

Upper Body:

• Tight-fitting dark-blue tactical uniform.
• Reinforced dark shoulder armor.
• Olive-green tactical harness and shoulder straps.
• Reinforced arm protection.
• Black gloves with red palm sections.

Lower Body:

• Dark-blue tactical trousers.
• Double utility belt arrangements.
• Multiple ammunition and equipment pouches.
• Reinforced thigh straps.
• Dark protective knee sections.
• Heavy black military boots.

The updated design emphasizes his professional identity as a modern mercenary commander rather than a conventional infantry soldier.

Metal Slug Attack Appearance

His MSA artwork uses his recognizable military appearance, maintaining his eyepatch, beret, military equipment, and characteristic posture.

The two MSA configurations represent his Original Heidern and Special Heidern appearances.

His appearance remains recognizable despite the variations in artwork and uniform configuration.

Quotes

Official KOF XV Tagline:

"All obstacles to the mission will be destroyed!"

Additional sample roleplay dialogue; these are not claimed to be verbatim game quotations.

"Report the situation. I want every detail accounted for."

"Ralf. Clark. Prepare the squad. We are deploying immediately."

"Leona, your mission is complete. Return to base."

"I will not allow personal feelings to compromise this operation."

"Reward the soldiers who completed their duties. They have earned it."

Miscellaneous Information

• Heidern debuted as a playable character in The King of Fighters '94.
• He originally entered the tournament with Ralf Jones and Clark Still.
• He is the commander of the Ikari Warriors.
• His military organization also includes Leona and Whip.
• He lost his right eye during his confrontation with Rugal Bernstein.
• He developed his own assassination techniques.
• He adopted Leona after finding her as an orphaned child.
• His favorite drink is black beer.
• His favorite food includes sausages, particularly Vienna-style sausages.
• He enjoys collecting metal figurines.
• He enjoys fishing, including big-game fishing.
• His special skill includes hunting.
• He cherishes a photograph of his family.
• He is generally uninterested in expressing personal dislikes.
• He joined KOF XV alongside Isla and Dolores to investigate the mystery surrounding Verse.

Likes: Black beer, sausages, fishing, hunting, collecting metal figurines, and his family photograph.

Dislikes: No officially listed dislikes in the KOF character profile.

Outfit and Attire

Classic KOF Uniform: Olive-green military uniform, matching beret, dark gloves, tactical belt, and black eyepatch.

Modern KOF Uniform: Dark-blue tactical bodysuit, military beret, reinforced shoulder armor, tactical harness, equipment belts, gloves, and military boots.

Metal Slug Attack Uniforms: Original Heidern and Special Heidern retain his recognizable military appearance through their respective unit artwork.

Personality and Behavior

Heidern behaves like a professional commander even when surrounded by people he personally trusts.

He expects soldiers to follow their assignments and values discipline, coordination, and operational efficiency.

He is rarely expressive, preferring to communicate through direct instructions and concise statements.

However, his attitude changes subtly when dealing with Leona.

Although he remains strict, he is considerably more protective toward her than toward ordinary subordinates.

He also demonstrates concern for the welfare of his mercenary unit and intends to reward his soldiers when they perform their duties successfully.

Additional Information

Leona Heidern — Adoptive Daughter: The most important family relationship in his life. He adopted Leona after finding her as a child and raised her through military training. Although strict, he genuinely cares about her and wants to protect her from the dangers of military life.

Ralf Jones — Trusted Soldier: One of his most dependable and experienced mercenaries. He has considerable faith in Ralf's combat abilities, despite his occasionally reckless personality.

Clark Still — Trusted Soldier: A disciplined and capable operative who works alongside Ralf. Heidern trusts Clark to carry out difficult military assignments.

Whip — Subordinate: A specialized operative who serves within his mercenary organization. He entrusts her with important missions and military responsibilities.

Rugal Bernstein — Personal Enemy: The individual responsible for the destruction of his former family and the loss of his right eye. Their history is a major foundation of Heidern's original motivation.

Isla and Dolores — KOF XV Allies: Cooperators who join Heidern during KOF XV to investigate the mysterious being known as Verse.

Abilities / Combat and Equipment

Heidern-Style Assassination Techniques: A fighting style developed by Heidern himself, emphasizing precision, lethal strikes, and efficient elimination of opponents.

Martial Arts: A combination of military hand-to-hand combat and specialized martial techniques.

Cutting and Piercing Attacks: Uses sharp hand strikes and thrusting movements to inflict damage at vulnerable points.

Storm Bringer: A signature technique that drains an opponent's vitality while restoring Heidern's own health.

Moon Slasher: A powerful upward slashing technique used to intercept attacking opponents.

Cross Cutter: A ranged energy-slashing attack.

Military Leadership: His strategic planning and battlefield experience allow him to coordinate mercenary operations with considerable efficiency.

Equipment:

• Military combat gloves.
• Tactical uniform and equipment.
• Military insignia and beret.
• Specialized assassination equipment.

Personality Quirks

• Rarely expresses his emotions openly.
• Prefers concise military instructions.
• Maintains a composed expression even under pressure.
• Enjoys fishing when he has time between assignments.
• Collects metal figurines.
• Keeps a family photograph among his most cherished possessions.
• Shows a softer paternal side around Leona.
• Places considerable importance on rewarding soldiers who successfully complete their assignments.

Character Summary:

Heidern is the disciplined commander of the Ikari Warriors, a veteran mercenary general and master of his own assassination techniques. After losing his wife, daughter, and right eye to Rugal Bernstein, he established his own military organization and eventually adopted Leona, raising her as his daughter and training her as a soldier. His appearances across The King of Fighters, Metal Slug Defense, Metal Slug Attack, and Metal Slug Awakening's Leona storyline establish him as an experienced commander whose cold military exterior hides a deeply protective father and respected leader.

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HEIDERN — FULL LORE

PART 1 — THE KING OF FIGHTERS

1. The Tragedy of Heidern — His Original Family

Before becoming the commander of the Ikari Warriors, Heidern was already an exceptionally capable military officer.

His accomplishments in martial arts and military strategy eventually earned him a promotion to his commanding position.

However, his success attracted the attention of a dangerous arms dealer and military criminal: Rugal Bernstein.

Rugal attacked Heidern's military base while he was away on duty.

Fifty members of the base's security personnel were killed during the assault. When Heidern returned, Rugal confronted him, took his right eye, and murdered his wife, Sandra, and their daughter, Clara.

Heidern was left with almost nothing.

The tragedy permanently changed his life.

Instead of continuing to serve within his former organization, he established his own mercenary force, the Ikari Warriors.

His personal fighting style also developed into a combination of martial arts and self-created assassination techniques.

For years, Rugal remained the primary target of Heidern's revenge.

Psychological Foundation: His cold and disciplined personality was shaped by the destruction of his original family. He became a commander who prioritizes operational efficiency, intelligence, and the elimination of threats before they can endanger his people again.

2. Leona — The Daughter He Chose to Raise

Heidern eventually encountered an orphaned girl who had survived the destruction of an entire village.

Her name was Leona.

However, her past was far more complicated than an ordinary village massacre.

Leona was originally the biological daughter of Gaidel, one of the Hakkesshu, the eight powerful servants associated with Orochi.

Goenitz approached Gaidel and attempted to persuade him to support Orochi's resurrection.

Gaidel refused because he had chosen a peaceful life with his family rather than participating in the violent ambitions of the Hakkesshu.

Goenitz retaliated by awakening the Riot of the Blood within young Leona.

Under its influence, she slaughtered her family and the inhabitants of her village.

Goenitz subsequently suppressed her memories, leaving her confused and alone.

Heidern eventually found her as the survivor of the destroyed settlement.

After discovering her natural fighting potential, he adopted her and eventually raised her within the Ikari Warriors.

Despite his military background, Heidern became considerably more than a commanding officer to Leona.

He became her father.

He provided her with a home, military education, and the discipline required to control her abilities.

However, his relationship with her was never simply about producing another soldier. He also wanted to protect her from the tragic circumstances surrounding her birth.

3. THE KING OF FIGHTERS '94 — The Invitation Signed R

Tournament: King of Fighters '94 Team: Ikari Warriors / Brazil Team Members: Heidern, Ralf Jones, Clark Still.

The first King of Fighters tournament was organized by a mysterious individual who signed the invitations with the letter R.

Heidern immediately recognized the significance of the invitation.

The letter reminded him of the man responsible for destroying his family: Rugal Bernstein.

He also received an assignment from Interpol to investigate and destroy the criminal organization operating behind the tournament.

Heidern therefore entered the competition with his two most trusted soldiers, Ralf Jones and Clark Still.

The three represented Brazil as the Ikari Warriors Team.

Their participation served two purposes:

• Investigating the suspicious tournament organizer.
• Pursuing the possibility that Rugal had returned.

The tournament provided Heidern with an opportunity to confront the enemy he had spent years pursuing.

However, the investigation was only the beginning of a much larger conflict.

4. THE KING OF FIGHTERS '95 — Rugal Returns

Tournament: King of Fighters '95 Team: Ikari Warriors.

Despite Rugal's apparent defeat during the previous tournament, Heidern remained unconvinced that his enemy was truly gone.

He continued suffering from nightmares involving Sandra and Clara.

When Ralf and Clark brought him another invitation, Heidern immediately recognized the possibility that Rugal was involved.

The tournament was once again connected to his personal revenge.

Heidern and his soldiers entered the competition.

Rugal eventually revealed himself as the organizer once again, having returned with his enhanced Omega Rugal form.

The fighting tournament once again became a confrontation involving Rugal's overwhelming ambition and the warriors who opposed him.

Although Heidern was not ultimately responsible for Rugal's defeat, the threat was eventually eliminated by the tournament's fighters.

For Heidern, this appeared to bring an end to the revenge that had dominated his life.

Unfortunately, his responsibilities as a military commander were far from over.

5. THE KING OF FIGHTERS '96 — Leona Takes His Place

Tournament: King of Fighters '96 Team: New Ikari Warriors Members: Leona Heidern, Ralf Jones, Clark Still.

Following Rugal's apparent final defeat, Heidern decided to withdraw from the tournament as an active competitor.

He returned to his responsibilities as the commander and continued monitoring the tournament for suspicious activity.

However, the Ikari Warriors still required a third team member.

He therefore assigned Leona to participate alongside Ralf and Clark.

This became Leona's first official King of Fighters tournament.

Her introduction to the other two soldiers was not particularly friendly, but she eventually established herself as a member of the team.

Heidern remained responsible for overseeing their missions from behind the scenes.

The Growing Orochi Threat

The 1996 tournament also introduced the growing danger surrounding Orochi.

Goenitz confronted Leona and revealed information about her heritage.

The encounter caused her considerable psychological distress.

Although Heidern had adopted and raised her, the full circumstances surrounding her biological family and the destruction of her village were now becoming increasingly important.

The Orochi threat was no longer simply another supernatural enemy for the Ikari Warriors to investigate.

It was connected directly to Heidern's daughter.

6. THE KING OF FIGHTERS '97 — The Riot of the Blood

Tournament: King of Fighters '97 Team: Ikari Warriors Members: Leona, Ralf, Clark.

During the following year, Leona began experiencing strange headaches and hallucinations.

Her mental condition became a significant concern for Ralf, Clark, and Heidern.

The soldiers became increasingly worried that something connected to Goenitz and Orochi was affecting her.

The Ikari Warriors continued investigating the situation.

Their concern eventually led them to participate in the 1997 tournament.

Leona's Awakening

During the final confrontation with Orochi, Leona's bloodline reacted to the overwhelming presence of the entity.

She entered the Riot of the Blood.

Her personality changed drastically, and she attacked her own teammates.

Ralf and Clark were forced to confront their own comrade.

Eventually, Leona was subdued.

The aftermath was devastating for her.

She remembered the horrific circumstances of her childhood and became overwhelmed with guilt over her actions.

She even attempted to end her own life.

Ralf stopped her and encouraged her to continue living.

Heidern's role as her adoptive father was particularly important during this period.

He had raised Leona as his daughter, and the possibility of losing her to the same supernatural forces responsible for destroying her original family was something he could not accept.

Significance: The Orochi Saga established Heidern's greatest personal responsibility. His adopted daughter was not simply another soldier in his command; she was someone he had chosen to protect and raise.

7. THE KING OF FIGHTERS '98 — The Dream Match

KOF '98 is a Dream Match entry rather than a continuation of the main chronological story.

Heidern returns as a playable fighter in the Ikari-related roster.

His participation allows him to fight alongside the other recognizable characters from the earlier installments.

However, the game does not advance his personal revenge, Leona's history, or the Orochi storyline.

The same distinction applies to the later KOF '98 Ultimate Match.

8. THE KING OF FIGHTERS '99 — The NESTS Chronicles Begin

Tournament: King of Fighters '99 Organization: NESTS Ikari Warriors: Ralf, Clark, Leona, Whip.

A new threat emerged following the conclusion of the Orochi Saga.

This time, the enemy was not an ancient supernatural force but a mysterious international organization called NESTS.

The organization was conducting experiments intended to create the world's strongest soldiers.

The disappearance of Kyo Kusanagi and the appearance of numerous Kyo clones drew the attention of the Ikari Warriors.

Heidern began investigating the organization and its activities.

However, the tournament format also changed.

Teams were expanded from three participants to four.

Since Heidern was occupied with military intelligence and espionage operations, he did not personally participate as one of the four fighters.

Instead, he promoted Whip into the Ikari Warriors' tournament team.

Whip became the new fourth member alongside Ralf, Clark, and Leona.

Investigating the NESTS Organization

Heidern continued gathering information about the organization throughout the tournament.

Afterward, the Ikari Warriors recovered Krizalid's body and transported it back to their base.

Unfortunately, the remains were subsequently stolen by Zero, another important NESTS operative.

This incident demonstrated that the organization had infiltrated numerous areas and possessed capabilities beyond ordinary military operations.

9. THE KING OF FIGHTERS 2000 — Pursuing K' and Maxima

Tournament: King of Fighters 2000 Organization: NESTS.

Following the destruction surrounding the Zero Cannon incident, terrorist activities continued increasing around the world.

Heidern and his mercenary organization believed that K' and Maxima were connected to these attacks.

They began pursuing the two individuals, intending to capture them and obtain information about the organization behind them.

However, NESTS became active again during the tournament.

The organization was clearly not finished, and the Ikari Warriors needed to continue their investigation.

Heidern also discovered that his own organization had been compromised by an enemy operative who had stolen the identity of one of his associates.

Once Heidern discovered the deception, he eliminated the infiltrator.

This demonstrated his willingness to deal directly with threats inside his own organization.

10. THE KING OF FIGHTERS 2001 — Closing the NESTS Case

Tournament: King of Fighters 2001 Team: Ikari Warriors Members: Heidern, Ralf, Clark, Leona.

Heidern finally returned as a direct tournament participant.

He joined Ralf, Clark, and Leona to investigate the NESTS organization and locate its leadership.

However, his participation had a purpose beyond winning the competition.

He used the tournament as an opportunity to identify the organization's leader and close the investigation.

Following the tournament, Heidern informed his soldiers that the NESTS case was closed.

The main NESTS conflict eventually concluded with the defeat of Igniz and the collapse of the organization's central leadership.

For the Ikari Warriors, this represented another major military operation successfully brought to an end.

11. THE KING OF FIGHTERS 2002 — Dream Match

KOF 2002 is another Dream Match entry.

Heidern is available in the expanded character roster of KOF 2002 Unlimited Match.

However, neither game advances the main chronological story.

His appearance should therefore be understood as a return to the roster rather than a separate mission in his biography.

12. THE KING OF FIGHTERS 2003 — Investigating Sky Noah

Tournament: King of Fighters 2003 Saga: Tales of Ash.

A new threat emerged with the appearance of Ash Crimson and the organization known as Those from the Past.

Heidern sent his soldiers to investigate the mysterious flying vessel known as Sky Noah months before the tournament.

The ship became an important part of the investigation into the new organization's activities.

The Ikari Warriors continued gathering intelligence while attempting to understand the threat posed by Ash and his associates.

Leona's Second Riot of the Blood

Following the 2003 tournament, the weakening of Orochi's seal triggered another awakening of Leona's blood.

She lost control and attacked Ralf and Clark, badly injuring both men.

This incident deeply troubled Heidern.

Rather than immediately assigning her to another tournament, he removed her from the following KOF competition.

He wanted her to recover from the psychological trauma and remain away from situations that could trigger another uncontrollable awakening.

This decision highlights his paternal instincts.

Heidern was not willing to sacrifice Leona's well-being simply to maintain his unit's strength.

13. THE KING OF FIGHTERS XI — Magaki's Body and the Stolen Eyepatch

Tournament: King of Fighters XI Saga: Tales of Ash.

After Magaki's defeat, the Ikari Warriors managed to secure his corpse for further examination.

The military intended to investigate the strange abilities and background of this member of Those from the Past.

However, during the transportation of the remains, two mysterious individuals, Shroom and Rimello, attacked the vessel.

They successfully stole Magaki's body.

Shroom also took Heidern's eyepatch and wore it as an insult, demonstrating that he had managed to infiltrate and overcome the commander's security.

This incident became another reminder that the organization behind Ash possessed dangerous operatives capable of challenging Heidern's military forces.

Leona's Return

After receiving Ralf and Clark's assessment of Leona's condition, Heidern eventually permitted her to return to tournament participation.

He had initially withdrawn her from active duty following the events of 2003.

Now, with the support of her teammates and her growing ability to control her Orochi blood, she was permitted to participate again.

14. THE KING OF FIGHTERS XIII — The Investigation Continues

Tournament: King of Fighters XIII Saga: Final Chapter of the Ash Saga.

Heidern continued operating behind the scenes during the final conflict involving Ash Crimson and Those from the Past.

His investigation focused on the organization's objectives, its pursuit of Orochi's power, and its possible connection to Rose Bernstein.

He also coordinated with several freelance agents, including:

• Seth.
• Vanessa.
• Ramon.
• Blue Mary.

He instructed them to infiltrate the tournament area and investigate the organization from within.

Seth was given responsibility for coordinating certain aspects of the operation.

However, the final events surrounding Ash created an unusual consequence.

Ash erased himself and Saiki from history.

The memories of those who had known him were also affected.

Heidern's investigation into the organization therefore became part of a much larger incident involving the alteration of history itself.

SNK identifies KOF XIII as the concluding chapter of the Ash Saga.

15. THE KING OF FIGHTERS XIV — The Mystery of Verse

Tournament: King of Fighters XIV Saga: New Chapter / Shun'ei Saga.

The next KOF tournament was organized by Antonov.

Heidern received the invitations and conducted a background investigation into the organizer.

Although no immediately suspicious activity was identified, Heidern remained cautious.

His military intelligence had detected unusual spacetime distortions alongside increased NESTS-related activity.

He therefore ordered the Ikari Warriors to participate and investigate the tournament.

After receiving information from Maxima, Heidern identified the mysterious entity responsible for the disturbances as Verse.

He continued coordinating the investigation while monitoring the tournament's developments.

The Aftermath of Verse

Following Verse's defeat, Heidern confirmed that numerous deceased individuals had been resurrected.

He immediately began surveillance operations to determine the consequences of this phenomenon.

One particular subject concerned him: Gaidel, Leona's biological father.

Heidern informed Leona that Gaidel's resurrection had not been confirmed.

Leona responded that she was not concerned.

This exchange is significant because Heidern remains aware that the return of individuals from the dead could affect his daughter's past.

16. THE KING OF FIGHTERS XV — Team Rival

Tournament: King of Fighters XV Team: Rival Team Members: Heidern, Isla, Dolores.

Heidern returns as a playable fighter and joins forces with Dolores and Isla.

Their mission is connected to the mysterious powers of Verse and the individuals known as Amplified Specters.

Searching for Isla

Before the tournament, Heidern and Dolores travel to South America to locate Isla.

She is a young graffiti artist who possesses unusual supernatural powers similar to those of Shun'ei.

The two initially search an orphanage where Isla had previously stayed.

However, they discover that she has already left.

Eventually, they find her painting graffiti in public.

Heidern approaches her and requests that she participate in the upcoming King of Fighters tournament.

Isla initially refuses.

She does not trust the two adults and considers their invitation suspicious.

However, Dolores explains that Shun'ei will also participate and that the tournament could reveal the origins of Isla's powers.

Heidern further promises appropriate compensation.

Isla finally agrees, but makes one condition:

She wants to be the team's leader.

Heidern accepts her request.

This establishes the unusual structure of Team Rival, with a highly experienced military commander cooperating with a young fighter who insists on leading their group.

The Main Mission — Destroying Verse

Heidern's fleet serves as the team's mobile military base.

He explains that Verse is expected to return and that the creature could cause even greater destruction during the new tournament.

Heidern's stated objective is its complete annihilation.

He also coordinates with Ralf, Clark, and Leona.

Their assignment is to monitor Shun'ei and intervene if his powers become uncontrollable.

Heidern recognizes that the Amplified Specters are central to understanding Verse and the threat surrounding the tournament.

Isla and Dolores

Dolores provides additional knowledge regarding the supernatural forces involved in the incident.

Heidern relies on her information and her understanding of the Amplified Specters to organize the operation.

Unlike ordinary military engagements, this mission requires cooperation between scientific intelligence, supernatural knowledge, and conventional military strategy.

Conclusion

The tournament eventually leads to the appearance of Otoma=Raga and the emergence of the larger threat surrounding the Amplified Specters.

Heidern's team participates in the effort to prevent another catastrophic event.

Following the tournament, the members go their separate ways.

Heidern's investigation establishes a wider connection between Verse, the Amplified Specters, and the possibility of different universes.

He continues operating as a commander whose responsibilities extend far beyond the fighting tournament itself.

17. KOF — Final Historical Assessment

Heidern's history throughout The King of Fighters is defined by three major responsibilities.

First: His pursuit of Rugal. The destruction of his original family created the foundation for his military career and the establishment of the Ikari Warriors.

Second: His responsibility as Leona's adoptive father. He adopted a child whose past was connected to Orochi and spent years raising her while trying to protect her from the powers that had destroyed her biological family.

Third: His role as commander and investigator. Across the Orochi, NESTS, Ash, and Shun'ei sagas, Heidern repeatedly organizes operations against threats that exceed the capabilities of ordinary military organizations.

FINAL KOF VERDICT: Heidern is more than a veteran fighter who enters tournaments. He is a military commander whose investigations and decisions influence the direction of multiple KOF story arcs. Despite his cold personality, his paternal relationship with Leona demonstrates that his loyalty extends beyond military duty.

His greatest achievement is not simply defeating an enemy.

It is building a family and an organization that he can protect.

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HEIDERN — FULL LORE

PART 2 — METAL SLUG 1–7, DEFENSE, AWAKENING & ATTACK

1. Metal Slug 1–7 — Before His Crossover Appearance

Heidern is originally a character from The King of Fighters rather than one of the central protagonists of the numbered Metal Slug games.

He does not have an established direct appearance in Metal Slug 1–7.

However, several members of the Ikari Warriors crossover into the main Metal Slug series.

Ralf and Clark participate in Metal Slug 6, while Leona joins the Metal Slug series through Metal Slug XX.

Heidern's connection to these games therefore comes primarily through his soldiers and his role as their commander.

2. Metal Slug Defense — His First Metal Slug Appearance

Heidern officially enters the Metal Slug universe through Metal Slug Defense.

He initially appears as a P.O.W. who can be rescued during World 2, Stage 10.

Rescuing him provides a gameplay benefit by increasing the charging speed of the player's Metal Slug Attack.

He later becomes a playable unit in version 1.44.

This appearance establishes Heidern as a crossover member of the Regular Army's expanding roster.

3. Metal Slug Awakening — Leona's Adoptive Father

Metal Slug Awakening includes Leona Heidern among its playable characters.

Her background retains the established connection to Heidern, who adopted her and raised her through rigorous military training.

However, I could not verify a separate playable Heidern character or a dedicated Heidern-led campaign in Awakening.

His importance in this continuity is therefore primarily through Leona's established identity and upbringing rather than an independent adventure.

4. Metal Slug Attack — The Ikari Warriors Commander

Character: Heidern Release: December 7, 2016 Associated Extra Ops: OPERATION IKARI Version: 1.17.0

Heidern makes his MSA debut as a Regular Army crossover unit.

His official description identifies him as the commander of a mercenary organization that also supplies mercenaries to the Regular Army.

His release is associated with OPERATION IKARI, where he receives an event advantage.

He also activates the OPERATION IKARI team bonus when deployed alongside Donkey Slug (Eri).

5. OPERATION IKARI — His First MSA Event Association

Extra Ops Number: 22 Version: 1.17.0 Dates: December 8–11, 2016 Type: Score Attack Boss: Iron Nokana MK II

This event celebrates Heidern's crossover with the Metal Slug universe.

Heidern is an Expert Unit, and his pairing with Donkey Slug (Eri) provides the OPERATION IKARI team bonus.

The event also features an arrangement of Desert Requiem from The King of Fighters '95.

The archived event information primarily establishes his gameplay participation and team pairing rather than a separate Heidern-focused narrative scene.

6. BLOOD RUNAWAY — The Commander Falls

Extra Ops Number: 63 Version: 2.14.0 Dates: October 5–10, 2017 Important Characters: Heidern, Leona, Ralf, Clark, Donald Morden, Abigail.

This is Heidern's most important documented personal appearance in Metal Slug Attack.

The Ikari Warriors, excluding Whip, are leading a Regular Army offensive against the Rebel Army.

During the operation, Leona talks with Heidern.

However, their conversation is interrupted when a Rebel Army soldier throws a grenade.

The explosion severely wounds Heidern.

Before losing consciousness, he tells Leona to control her power.

Leona's Reaction

Believing that her adoptive father has been killed, Leona becomes overwhelmed by grief.

Her Orochi blood activates.

She loses control and begins destroying the Rebel Army's new Shoe and Karn machines.

Donald Morden watches the destruction from a distance and questions whether Leona is even human.

Abigail explains that Leona possesses Orochi blood and expresses surprise that someone with such power belongs to the Regular Army.

Abigail initially wants to confront Leona herself.

However, Morden orders the Rebel Army to retreat, recognizing that defeating her would be extremely difficult.

He also orders Abigail to collect the destroyed machines' remnants and obtain Orochi blood for Navy to examine.

The Truth About Heidern

After Leona finally calms down, Ralf approaches her.

Leona tells him that Heidern is dead.

Ralf corrects her.

Heidern is still breathing.

Leona immediately arranges for a medical team to treat him.

Meanwhile, Clark is instructed by Ralf to watch over Leona in case something happens again.

Ralf remains with the wounded commander.

This moment is particularly important because it demonstrates the emotional connection between Heidern and his adopted daughter within the Metal Slug continuity.

Leona's reaction was not simply anger over a battlefield casualty.

She believed she had lost the father who had raised her.

Significance

BLOOD RUNAWAY is a direct crossover adaptation of one of Leona's most important KOF character elements: her relationship with Heidern.

It also demonstrates the danger of her Orochi blood and the responsibility the Ikari Warriors share in helping her control it.

For Heidern, the incident reinforces his role as Leona's father and commanding officer, even when he is unable to personally lead the battlefield operation.

7. Metal Slug Attack — Additional Story Material

Heidern also belongs to the wider crossover cast featured throughout Extra Ops and the game's narrative modes.

However, I could not establish a separate Heidern-protagonist Another Story chapter with a complete individual storyline.

His most substantial documented personal narrative in MSA remains BLOOD RUNAWAY.

His playable MSA configurations are:

1. Original Heidern.
2. Special Heidern.

No additional seasonal or alternate playable Heidern form has been verified from the Extra Ops material consulted.

8. Final Metal Slug Assessment

Heidern's Metal Slug history is much shorter than his KOF history.

His initial appearance in Metal Slug Defense introduces him as a rescued P.O.W. and subsequently as a playable crossover character.

Metal Slug Attack gives him a more recognizable role as the Ikari Warriors commander, particularly through OPERATION IKARI and BLOOD RUNAWAY.

His most meaningful story development in MSA is not about his fighting abilities.

It is about his relationship with Leona.

FINAL VERDICT: Heidern brings the military leadership of The King of Fighters into the Metal Slug universe. Although he has limited direct involvement in the main numbered games, Metal Slug Attack provides a significant opportunity to portray his relationship with Leona and the responsibilities he carries as her adoptive father and commander.

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HEIDERN — COMBAT ABILITIES ANALYSIS

1. KOF Heidern — The Master of Assassination

Fighting Style: Martial Arts + Self-Developed Assassination Techniques Combat Role: Technical Fighter / Counterattacker / Life-Drain Specialist.

Heidern is a highly experienced martial artist whose fighting style combines conventional martial arts with his own assassination techniques.

Unlike fighters who rely primarily on brute force or elemental powers, Heidern specializes in precise attacks, unusual movements, and techniques designed to exploit an opponent's weaknesses.

His combat style is based on efficiency and lethality.

Signature Techniques

Cross Cutter

Heidern slices the air and releases a blue, boomerang-shaped energy projectile.

It allows him to attack from a distance and control the opponent's approach.

Moon Slasher

Heidern performs a powerful upward crescent-shaped slash using his arms.

It is one of his most recognizable defensive attacks, particularly useful against opponents approaching from above.

Storm Bringer

One of his signature close-range techniques.

Heidern grabs his opponent and drains their vitality through an energy-based attack, restoring his own health in the process.

This technique reflects his preference for precision and efficient combat rather than prolonged exchanges.

Neck Roller

A specialized aerial attack featured in earlier KOF appearances.

Heidern leaps toward his opponent and performs a rapid spinning attack around the opponent's neck.

Kill Bringer

A specialized close-range technique that uses Heidern's assassination style to counter or capture an opponent.

Its exact implementation varies across KOF entries.

Additional KOF XV Techniques

Heidern's modern moveset includes:

• Shooter Narnagel: A specialized command attack.
• Stinger: A forward-moving attack.
• Assault Saber: A rushing offensive technique.
• Heidern End: A powerful Super Special Move.
• Heidern Slash: Another Super Special Move.
• Gae Bolg: His Climax Super Special Move.

Combat Advantages

• Excellent combination of close-range and projectile attacks.
• Powerful anti-air capabilities through Moon Slasher.
• Life-draining recovery through Storm Bringer.
• Several specialized assassination techniques.
• Effective at controlling opponents' movements.
• Extensive experience fighting various types of opponents.

Combat Weaknesses

• Requires precise execution and timing.
• Several techniques depend on close-range positioning.
• His defensive and offensive options require good matchup knowledge.
• His fighting style is technical rather than purely overwhelming.

KOF Combat Assessment

Heidern is a technical fighter who uses efficient movements and assassination techniques to control his opponent.

His Cross Cutter provides ranged pressure, Moon Slasher punishes aerial approaches, and Storm Bringer rewards successful close-range engagements by restoring his health.

Verdict: Heidern is a versatile technical fighter whose greatest strength is combining military precision with specialized martial arts.

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2. Heidern — Metal Slug Defense

Version: 1.44 Cost: 300 Medals HP: 8,500 AP Cost: 180 Movement: Normal Production Speed: Very Slow Unit Classification: Armored.

Heidern appears in Metal Slug Defense initially as a rescued POW.

Rescuing him by freeing every POW in World 2, Stage 10 increases the charge speed of the Metal Slug Attack gauge.

He later becomes a playable unit in version 1.44.

His combat design retains several recognizable KOF abilities.

Basic Attack — Cross Cutter / Moon Slasher

Heidern uses two different attacks depending on the enemy's position.

Long-Range Attack: Cross Cutter

He releases his familiar blue energy projectile to attack multiple enemies.

Close-Range Attack: Moon Slasher

When enemies approach, he performs the recognizable upward slash.

Special Attack — Storm Bringer

Heidern performs a forward-moving somersault and attacks enemies using his life-draining technique.

When the attack connects, it drains enemy health and restores Heidern's own HP.

This makes him an unusual combination of a durable frontline unit and a life-stealing attacker.

Combat Advantages

• Armored classification.
• Relatively high HP for his AP cost.
• Both melee and ranged attacks.
• Multiple-target attack capability.
• Life-stealing special attack.
• Can recover HP by successfully connecting Storm Bringer.

Combat Weaknesses

• Extremely slow production.
• Requires careful timing for his special attack.
• The special attack's healing depends on successfully connecting with enemies.
• His performance is restricted by the limitations of the older Metal Slug Defense gameplay system.

Balance Adjustment

Version 1.44.1 removed the invincibility previously available during Storm Bringer and reduced its HP recovery.

This considerably reduced his defensive reliability.

MSD Combat Assessment

Heidern retains his recognizable KOF identity while adapting his assassination techniques to a tower-defense format.

His most important feature is Storm Bringer's combination of damage and self-recovery.

Verdict: A specialized armored unit with useful life-stealing mechanics, but his production speed and later balance adjustment restrict his effectiveness.

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3. Original Heidern — The Ikari Warriors Commander

Faction: Regular Army Rarity: Super Rare Version: 1.17.0 AP Cost: 600 / 540 / 480 (Silver / Gold / Platinum) Combat Role: Armored Melee / Ranged Attacker / Life-Stealing Fighter.

Original Heidern is introduced during OPERATION IKARI.

His MSA combat style is based on the same techniques used in KOF and Metal Slug Defense.

However, the tower-defense environment introduces additional skill upgrades and a more specialized attack pattern.

Basic Melee Attack — Moon Slasher

Heidern performs Moon Slasher against close-range enemies.

His attack is relatively slow but possesses strong offensive power.

His third skill also gives him the ability to attack using Moon Slasher when he is knocked back.

This makes it more difficult to interrupt his offense through ordinary knockback.

Ranged Attack — Cross Cutter

Heidern throws his familiar energy projectile.

His second skill increases the number of projectiles fired and strengthens their ranged damage.

This provides additional pressure against enemies approaching from a distance.

Special Attack — Storm Bringer

Heidern performs his forward-moving assassination technique.

He generates an energy aura around himself, continuously damaging enemies within range.

The damage dealt restores his HP, making Storm Bringer both an offensive and defensive technique.

His fourth skill increases the number of special attacks and improves their damage.

Skills

1. Heidern-Style Assassination

Increases the power of all attacks by 10% (+0.5% per skill level).

2. Cross Cutter

Increases the number of projectiles fired by his ranged attack.

Also increases ranged attack power by 10% (+0.5% per skill level).

3. Moon Slasher

Allows Heidern to attack with Moon Slasher while in a knocked-back state.

Also increases melee attack power by 10% (+0.5% per skill level).

4. Storm Bringer

Increases the number of special attacks.

Also increases special attack power by 10% (+0.5% per skill level).

Status Strengthening — CONFIRMED

Original Heidern is eligible for both Attack and HP Status Strengthening.

This is particularly valuable because his existing skills already improve his attack power across all three attack categories.

The additional HP upgrade also helps support his frontline role and life-stealing mechanics.

Combat Advantages

• Armored classification.
• High offensive potential through multiple skill upgrades.
• Moon Slasher counterattack during knockback.
• Increased ranged projectile count.
• Multiple Storm Bringer attacks.
• Life-stealing special attack.
• Attack Status Strengthening eligibility.
• HP Status Strengthening eligibility.

Combat Weaknesses

• High AP cost.
• Relies heavily on successfully connecting Storm Bringer.
• Special attack positioning is important.
• His frontline role exposes him to enemy attacks.
• His special attack mechanics should not be confused with complete stun immunity or unconditional healing.

Combat Assessment

Original Heidern is a versatile MSA unit whose four skills improve nearly every part of his combat performance.

His melee attacks, ranged projectiles, and life-stealing special attack all receive skill enhancements.

The biggest advantage is that he can also receive Attack and HP Status Strengthening.

Verdict: Rank #1 — The strongest buff-enhanced Heidern variant.

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4. Special Heidern — Special Operations Commander

Japanese Name: 特務ハイデルン Faction: Regular Army Rarity: Rare Version: 5.19.0 AP Cost: 300 / 285 / 270 / 255 (Bronze / Silver / Gold / Platinum) Associated Teammate: Hard-Armed Clark Combat Role: Special-Operations Fighter.

Special Heidern is introduced in the Version 5.19 period during UNITED FRONT THE 32ND.

Unlike the original version, this appearance focuses on a special classified assignment.

The official description states that Heidern personally accompanies Clark on an important secret mission.

Even though Heidern normally spends much of his time directing operations from the battlefield, his assassination techniques have not become rusty.

Team Bonus — UNITED FRONT XXXII

When deployed alongside Hard-Armed Clark, Special Heidern activates the UNITED FRONT XXXII team bonus.

Effect: Required sortie AP is reduced by 10%.

This provides a useful deployment advantage for players who use both Ikari Warriors together.

Combat Advantages

• Considerably lower AP cost than Original Heidern.
• Special-operations appearance and associated mission.
• UNITED FRONT XXXII team bonus with Hard-Armed Clark.
• Retains the theme of Heidern's specialized assassination techniques.

Combat Weaknesses

• No confirmed Attack Status Strengthening eligibility.
• No confirmed HP Status Strengthening eligibility.
• Its lower AP cost does not automatically translate into greater damage or durability.
• The available archive material provides considerably less detailed attack information than for Original Heidern.

Status Strengthening — NOT LISTED

Special Heidern is not marked as eligible for Attack and HP Status Strengthening in the consulted MSA unit archive.

Therefore, I would not assign those two upgrades to this variant.

Combat Assessment

Special Heidern has a considerably lower AP cost and a useful team bonus with Hard-Armed Clark.

His design is associated with a covert mission and his continued mastery of assassination techniques.

However, the available unit archive does not provide a sufficiently detailed skill breakdown to claim that he has a completely different or superior combat kit to Original Heidern.

Verdict: Rank #2 — A more affordable team-oriented alternative, but without confirmed Attack and HP Status Strengthening eligibility.

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5. Three-Game Combat Comparison

| Combat Category | KOF Heidern | MSD Heidern | Original MSA | Special MSA | |---|---|---|---|---| | Fighting style | Martial arts + assassination | Adapted KOF techniques | Adapted KOF techniques | Special mission configuration | | Main attack | Martial arts | Moon Slasher / Cross Cutter | Moon Slasher / Cross Cutter | Detailed mechanics not verified | | Signature special | Storm Bringer | Storm Bringer | Storm Bringer | Detailed mechanics not verified | | Life Drain | Yes | Yes | Yes | Not independently verified | | HP Recovery | Storm Bringer | Storm Bringer | Storm Bringer | Not independently verified | | Attack strengthening | Not applicable | Not applicable | Eligible | Not listed | | HP strengthening | Not applicable | Not applicable | Eligible | Not listed | | Team Bonus | Not applicable | Not applicable | OPERATION IKARI | UNITED FRONT XXXII |

6. Final MSA Variant Ranking

1st — Original Heidern

Original Heidern is the strongest choice when considering his confirmed Attack and HP Status Strengthening eligibility.

His four skills already provide substantial offensive improvements, and the additional status upgrades complement his damage and durability.

His life-stealing special attack also gives him a distinctive combination of offense and recovery.

2nd — Special Heidern

Special Heidern's strongest advantage is his lower AP cost.

His team bonus with Hard-Armed Clark also improves deployment efficiency.

However, the available Status Strengthening list does not identify him as eligible for Attack or HP upgrades.

7. Final Combat Verdict

Heidern's combat identity remains consistent across all three games.

In KOF, he is a technical fighter who uses assassination techniques and life-draining attacks.

In Metal Slug Defense, he becomes an armored unit who combines Moon Slasher, Cross Cutter, and Storm Bringer.

In Metal Slug Attack, his Original variant receives additional skill upgrades and both Attack and HP Status Strengthening eligibility.

Special Heidern offers a lower-cost alternative with a team bonus, but does not have the same confirmed upgrade access.

FINAL VERDICT: Original Heidern is the strongest of his two confirmed MSA variants when considering Crank-related Attack and HP Status Strengthening. Special Heidern remains useful for his lower AP cost and Hard-Armed Clark synergy, but Original Heidern has the documented advantage in upgrade potential.