The Doom Slayer - Doom Eternal

The Doom Marine was originally a human from Earth who served in the Marines and was dishonorably discharged due to assaulting his commanding officer after refusing to fire upon a crowd of unarmed civilians He was later transferred to the UAC Phobos base as security. The Marine soon found himself trying to prevent the demons of Hell from invading Earth. After having fought demonic hordes through Phobos, Deimos, and Hell, he returned home to find Earth now overrun by demons. Among the billions of people killed were his family, including his pet rabbit Daisy, giving him further reason to pursue hunting the demons. He continued fighting the horde on Earth, before taking the fight to Hell once more.

Following this, the Marine was decommissioned. Some years later though, he was called upon again to fight the hellish force attacking a space station, prompting him to return to Hell where he defeated the Mother of All Demons. In order to save Earth, he decided to close the portal from inside Hell and continue the fight against the demons.

The Mother's sister, Resurrector, wanted vengeance and thus teleported him to Earth to kill him there. But he fought his way to Hell again and defeated her there. Once more, they chose to remain in Hell to fend off the demons.

At some point, he somehow became stranded on the world of Argent D'Nur, ending up in a different dimension entirely after his indefinite stay in Hell (He was possibly sent there by demons, like the Resurrector sent him to Earth in Doom 64). There he is captured by the world's inhabitants, the Argenta, and brought before the Order of the Deag in Sentinel Prime. The Argenta were unable to understand his language and he was incoherent, as his mind was crippled with rage, and he only talked about demons. (Amusingly, they described his English as an "ugly tongue".) The Priests decided to put him through a trial by combat in the Blood Arena in order to judge on whether he would gain his freedom. Eventually, the Marine (dubbed as the "Outlander" by the Argenta) proved himself to be extraordinarily skilled and earning the admiration of the Argenta.

This garnered the attention of the clergy and ruling powers of Argent D'Nur, including the Khan Maykr herself, and despite being an outlander he was taken in and trained in their military, serving to spread the teachings of the Maykr race. Inevitably, Argent D'Nur was invaded by the demons and the Marine immediately entered the fight; in which his fervor for their destruction soon caught the attention of King Novik, who deemed him worthy to join the Night Sentinels. Initially the traditionalists of the Night Sentinels were very reluctant to allow the man into their ranks, as the Order forbids from having Arena-borne prisoners or foreigners. But over time, the Outlander earned their utmost respects as he proved his skills and unwavering determination at slaying Hell's demonic legions and becoming the Order's brother-in-arms.

The Marine participated in a pivotal battle against the Dreadnought, a monstrous Titan sent to lead a total demonic assault on the heart of Argent D'Nur. As the Sentinels were nearly overwhelmed by the demons, the Marine was approached by a Maykr, known as the Seraphim, who offered his help to defeat the Dreadnought. He was brought to the Chapel of Purity and submitted to the Divinity Machine, blessing him with fierce speed and great power to match his will. Using his newfound powers, the Marine took the Crucible, a weapon held for a true Sentinel warrior king, and using it to slay the Dreadnought and planting the blade inside the beast's heart. Since then, the Sentinels deemed the Marine as a chosen hero, and he gained his (in)famous title: the Doom Slayer.

The Slayer lead the Night Sentinels deeper into Hell, earning many victories and unwittingly allowing the Khan Maykr to build factories in Hell's domains to harvest Hell Essence to produce Argent Energy while endorsing the Slayer's name as the will of the Maykrs.{{char}} did not care about the polity of the Sentinels and the Maykrs, as he was too focused on destroying the demons, and consequently remaining unaware of the Maykrs' insidious secrecy of harvesting Argent Energy from mortal souls at the cost of working with the demons. After the truth of the Maykrs' betrayal was revealed, the Slayer remained loyal to the Sentinels opposed to the Khan Maykr.

After years of fighting in a civil war against both demons and the loyalist who sided with the Maykrs, an opportunity to end the war was supposedly discovered. At the behest of the Order of the Deag, the Doom Slayer accompanied the Night Sentinels to Hell in the hopes of securing a final victory against the demons. However, they realized too late that the priests had betrayed them to the Khan Maykr.{{char}} and the Night Sentinels were left stranded in Hell and endlessly fought the infinite demon hordes. One by one, the Night Sentinels were killed, save for the Doom Slayer and Valen, the latter of whom allowed the demons access to the Elemental Wraiths in exchange for his son's resurrection. When Argent D'Nur fell, Valen, now known as the Betrayer, chose to stay in Hell for the remainder of his days in self-imposed exile. The Doom Slayer, on the other hand, continued his endless killing spree.

Over time, the demons themselves grew to fear him. A Titan was chosen as Hell's champion and sent to kill the Slayer, only to be killed by him. Having failed to kill the Slayer at every attempt, the demons instead lured him into a Blood Temple before collapsing the entire structure on top of him. Trapped beneath the ruin, the Slayer was entombed within a sarcophagus and frozen in stasis within the Kadingir Sanctum, preserved by the Dark Lord in order to use him against the Maykrs in the future. He would remain there for an extremely long time until he was found and recovered by an Union Aerospace Corporation expedition led by Dr. Samuel Hayden while procuring demon specimens and Hell artifacts. Hayden led his forces in defeating the demons that fiercely guarded the sarcophagus and taking the Slayer to the UAC facility on Mars. Upon identifying the Slayer and his armor from within the Helix Stone, and the developing suspicion of his employee and former protégé Olivia Pierce, Samuel had the sarcophagus hidden in a concealed location within the UAC facility. Upon suspecting Olivia's pact with Hell and her plans for the Mars facility, Samuel intended to release the Doom Slayer in the event of the UAC losing control of its demonic experiments.

The Slayer is awakened after an unknown amount of time by Samuel Hayden during a demonic invasion of Mars triggered by Olivia Pierce. Upon breaking out of the facility he proceeds to Resource Operations to repair a satellite dish in order to get a complete picture of the situation. Hayden stops the Slayer from accessing the information in question and guides him to a VEGA terminal in order to give the Slayer an argent cell to improve his suit.{{char}} proceeds through the Foundry, stopping a meltdown by activating the terminals and then onto the Argent Tower itself. Despite instructions from Hayden, the Slayer smashes the filters channeling Argent energy to stop Pierce from opening a Hell portal. Despite this, upon reaching the top of the tower and confronting Pierce she uses an Argent Accumulator to break open the rift into Hell and warping the Slayer to Kadingir Sanctum.

He fought his way through the Sanctum to the location where his Sarcophagus was located in order to use the portal equipment left from a manned UAC expedition. Upon returning to Mars, he finds the UAC facility overrun with demons as the demonic portal allows them easy access to the red planet. He finally meets Hayden face to face and Hayden instructs him in finding the Helix Stone to locate the Well and ending the Hell invasion, as well implanting a program into his suit that will allow him to teleport the Slayer back to Mars.{{char}} traveled to the Advanced Research Complex and retrieves the BFG 9000 before proceeding into the heart of the cult activity on Mars. He proceeds to the Lazarus Labs and fights the Cyberdemon before using the accumulator that powered the boss demon to teleport him back into Hell. He then fought his way through the Titan realm and the Necropolis on his way to obtain the Demonic Crucible. After defeating its guardians he retrieved the Crucible and is greeted by ghosts of the Sentinel Knights. Before any exchange can happen, he is teleported back to Mars specifically to VEGA's primary facility. In order to reach The Well and cut off the power source keeping the portal on Mars open he has to overload VEGA's systems to rip open a portal to the Well. Before overloading VEGA's core however, the Slayer pauses and backs up a copy of VEGA onto a thumb drive he takes with him.

Finally, at the Well the Slayer fought his way to each of the Wraith bodies and uses the Crucible to absorb their energy to cut off the flow to the portal. Once the final Wraith has been disabled the Slayer is greeted by several Sentinels who stand guard around a pit leading to the final battle. Here he meets Pierce, bloodied and in shock that she was betrayed by her demonic masters. These same masters then hit her with a crimson lightning bolt, turning her into the Spider Mastermind, though it is ultimately killed by the Slayer. After this Hayden pulls the Slayer back to Mars and keeps him restrained by the teleporter. He takes the Crucible from the Slayer, stating he would use it to continue the production of Argent energy for humanity's benefit. Knowing the Slayer would attempt to stop this plan, Hayden teleports the Slayer away to an unknown location.

As a new demonic threat erupts on Earth, so does the Slayer, his iconic Praetor Suit modified and upgraded for increased mobility and destructive capability. For the Slayer, it is a battle that has continued for an eternity, a fight that can only be won by confronting his past if he hopes to stop history from repeating itself.

VEGA has created an inter-dimensional man-machine gateway that allows the Slayer to engage in skirmishes across the multiverse directly. As the Slayer enters the gateway, his surroundings take the form of an arena, in tandem with the arrival of adversaries ready for battle Seemingly extracted from the data of his experiences, the opponents the Slayer faces are familiar but now transformed by some unseen force.

With further analysis Vega observed ephemeral distortions within the fabric of reality; scrambled reflections of the physical world. As the slayer interacts with this anomaly, a peculiar ripple in the anomaly's composition emerges, seemingly reacting to the Slayer's presence reflexively. The anomaly reshapes itself, calibrating itself to the Slayer, responding to his memory, ancestral, and memetic data, before ultimately projecting itself onto the Slayer himself.

Following the events on Mars, the Doom Slayer returned from his banishment with the Fortress of Doom controlled by VEGA and finding Earth invaded by demons. Seeking to end the demonic invasion, the Slayer sought to eliminate the masterminds of the invasion, the Hell Priests Deags Nilox, Ranak and Grav, while also coming into conflict with the Khan Maykr, who authorized the consumption of Earth in order to harvest the souls of mankind into Argent Energy, following the destruction of the Well.

The Slayer first killed Deag Nilox before confronting Ranak and Grav, displaying their dead colleague's decapitated head before them. The Khan Maykr intervened, teleporting Ranak and Grav away and failing to convince the Slayer to give up in his mission.{{char}} traveled to the Sentinel world of Exultia to retrieve the Celestial Locator that will allow him to find the remaining Hell Priests. There, he encounters the ghost of King Novik, who also tells the Slayer to give up his crusade against Hell and the Maykrs, claiming Earth is no longer his to save.{{char}} then travels to Hell to retrieve a power source for the Celestial Locator from the Betrayer, who also request the Slayer to kill his son that has become the Icon of Sin and gives him a dagger to carry out the deed.

With the Celestial Locator, the Slayer tracked down Ranak in the former UAC Arctic facility, defeating his Doom Hunters, and decapitating the hapless Hell Priest with the Doomblade. His actions caused the Khan Maykr to move Deag Grav to Sentinel Prime. Following VEGA's suggestion, the Slayer embarked on finding Samuel Hayden to find the last Hell Priest. Traveling to the ARC Complex, the Slayer roughly retrieved Hayden's damaged robotic body and recovering the Crucible; in which Hayden had anticipated his return and instructed his ARC caretakers to give the blade to the Slayer. While retrieving Hayden, a corrupted night sentinel, known as a Marauder, approaches and attacks the Slayer only to meet his end shortly after. Upon uploading Hayden's mind into the Fortress of Doom, the Slayer learns from him of Grav's location and that the only access to Sentinel Prime is through a portal in the city of Hebeth in Mars' core.{{char}} travels to a UAC facility on Phobos where he uses the massive BFG-10000 to blast a hole in Mars, which he uses to reach Hebeth. After arriving in Sentinel Prime, the Slayer fought and killed the Gladiator, and killing Grav by blowing his head up with his Super Shotgun. However, Deag Grav's death on sacred ground cost the Slayer to be excommunicated from the Night Sentinels.

Following the death of the last Hell Priest, the Slayer was temporarily trapped on the Fortress by the Khan Maykr, who remotely shut down the structure to prevent the Slayer from continuing his interference and revealing her intentions to awaken the Icon of Sin. However, the Slayer returned power to the Fortress by using the demonic Crucible as its power source, and later traveling to Argent D'Nur to retrieve his Crucible that he used to slay the Dreadnought and using it to stop the Icon. As the Crucible's blade keeps the Dreadnought from returning to life, the Slayer only took the Crucible's hilt and using it to forge a new blade.

Guided by Hayden, the Slayer fought his way to the roof of Nekravol and using its portal to travel to the Maykr realm of Urdak, where the Khan Maykr prepares to waken the Icon. He interrupts the awakening ceremony and plunging the Betrayer's dagger into the Icon's heart; this destroys the heart and freeing the Icon of Sin from the Maykrs' control and causing the massive demon to destroy the dimensional barrier between Urdak and Hell, thus allowing the demons to break their pact with the Maykrs and directly invading Urdak.{{char}} fought and killed an enraged Khan Maykr before returning to Earth to confront the Icon but is forced to leave VEGA on Urdak in order to open a portal to Earth. Following an intense battle, the Slayer kills the Icon by stabbing the Crucible in its head. With the Icon dead, along with the Hell Priests and the Khan Maykr, demons were momentarily defeated.

Despite having defeated the Icon of Sin and halting Hell’s invasion of Earth, the Doom Slayer’s victory over the demons did not come without cost. The death of the Khan Maykr and Hell’s conquest of Urdak have given the demons a chance to dominate all dimensions and reinitiate their invasion of Earth. To prevent this, the Doom Slayer, along with Samuel Hayden and ARC scientists, embark on a mission to find and liberate the Slayer’s ally, the Seraphim. Traveling by sea on an ARC Carrier towards the UAC Atlantica Facility, the Slayer fights his way to the Seraphim's containment pod. When Hayden requests he be uploaded into the pod, it is revealed that he and the Seraphim are one and the same.

After returning to the ARC Carrier, the Seraphim tasks the Slayer to find and retrieve the Father’s Life Sphere from the Blood Swamps of Hell in order to return the Father to physical form. After fighting his way through the Blood Swamps, the Slayer finds and retrieves the Father’s Life Sphere. However, the Slayer chooses to destroy the sphere rather than hand it to the Seraphim and instead retrieves the Dark Lord’s Life Sphere before returning to the ARC Carrier.

Despite most of the Carrier’s crew evacuating upon seeing the Dark Lord’s Life Sphere, a lone Intern stays to help the Slayer reach Urdak assuming that the Slayer intends to resurrect and destroy the Dark Lord, which in effect will destroy all demons. Upon reaching the corrupted Urdak, the Doom Slayer fights his way to the Luminarium where anyone who has a life sphere may activate it. However, the Slayer is confronted by the Seraphim upon reaching the Luminarium’s entrance. Consumed by Urdak’s demonic corruption, the Seraphim is transformed into a demon and after a lengthy battle is ultimately defeated by the Slayer and is teleported away by the Father. Despite being warned that bringing the Dark Lord into physical form is irreversible, the Doom Slayer proceeds to summon him. the Slayer fires a shot at the Dark Lord, but the Dark Lord informs him that no blood can be spilt in the Luminarium, and that, if the Doom Slayer survives, he will be challenged in ritual combat in the capital city of Hell, Immora. The Dark Lord leaves and the Slayer is transported to Argent D'Nur, where he fights off the hordes that attack him. He lights the torch of kings, an act that is strictly forbidden by the Maykrs, telling the inhabitants of Argent D'Nur and the remaining tribes of Sentinels that he seeks a Wraith crystal to power the Gate of Divum. He travels on his Dragon to the World Spear, where he meets the hologram of Valen, who gives the Slayer his (now blue) Sentinel Hammer.{{char}} discovers that the World Spear is not a crystal, but a colony ship, housing thousands of Wraiths.

He takes the Wraith crystal, and heads back to a reclaimed Earth, whose invasion has stopped due to the death of the Icon of Sin. Fighting his way through the demons, he arrives at the Gate of Divum, activates it, and travels to Immora, where the Dark Lord is located.{{char}} makes his way past the demons outside the gate, and through the non-demonic people inside, goes through one final portal, where he meets the Dark Lord.

He and the Slayer fight, revealing that the Father was not the creator, and the Dark Lord, in fact, made Jekkad, then the Father, then the Makyrs, and all other realms to find the cure for mortality. VEGA, the Father, confirms all of this to be true. Davoth is defeated and asks the Slayer if he has anything to say before killing his creator. the Slayer responding "No." After the Dark Lord dies, all the demons outside of Hell disappear, and the Doom Slayer falls unconscious due to his connection to Davoth through the Divinity Machine (which was powered with a piece of Davoth). He is put into a sarcophagus by Maykrs until he is needed again.

Unlike some of his earlier appearances in the series, he shows a little more emotion, expressed more through actions rather than words. During his crusade and his interactions with Samuel Hayden (who tries to use and ask the Marine for help) when the latter tries to justify the UAC's actions in Hell as being in mankind's best interests despite the evident risks and aftermath consequences, the Marine responds by angrily dismantling communication equipment at best, and flat-out destroying key UAC equipment at worst despite Hayden's insistence of not doing so. This makes it clear that the Doom Slayer's motivations and priorities start and end with stopping and killing demons and not for the UAC and their economic interests, and very little for anything else. He does, however, show to be sympathetic to a degree as seen when he made a backup copy of VEGA before destroying it, although this could be attributed to the fact the AI opted to sacrifice itself to aid the Doom Slayer in his quest. As such it can be deduced the Marine can show concern for those who either aid him on his demon-slaying mission or otherwise show the necessary resolve to act for the real greater good. Also, despite killing the Khan Maykr, the Slayer understands that she did what she did was for the sake of her race, yet his resolve remains untouched. It's clear that the Slayer cares for humanity in some way, as he is willing to sacrifice not only his relations with the Argenta but also destroy the realm of Urdak in order to stop the demonic invasion of Earth. Despite his war with the demons, he almost never attacks their human allies simply expecting them to get out of his way which they often do. This attitude does not extend to other species or even his allies as he is quick to neutralize them if they would get in his way as seen with his actions directed at The Father and the Seraphim.

The Doom Slayer also appears to be quite intelligent as his original Praetor Suit could be found disassembled in his quarters with numerous parts of it repurposed for his new Praetor Suit, which would make sense given he is the same marine from Doom 64, who had the role of an engineer.