• Limitless. * Blue. * Incredible cursed-energy control. * His ridiculous natural talent. But he doesn't have Red or Hollow Purple yet, because he hasn't mastered positive cursed energy. His Infinity also isn't the fully automated, constantly optimized defense that canon Gojo eventually develops. He's still exceptionally powerful—he simply hasn't become the Satoru Gojo yet. And because Suguru remains beside him, Gojo doesn't develop the same lonely philosophy of:

“I'm the strongest.”

It's much closer to:

“We're the strongest.”

---

Suguru Geto Never Falls

Geto still struggles. He still consumes curses. He still experiences their disgusting taste. He still witnesses how cruel ordinary humans can be toward sorcerers. And eventually he still discovers Mimiko and Nanako being abused by their village. That moment nearly pushes him over the edge. Except this Geto isn't isolated. Haibara is alive. Gojo is still his best friend. Yaga is still present. And Geto hasn't spent years silently drowning in trauma after Riko's death. Instead of massacring the village, Geto rescues the girls. Mimiko and Nanako eventually become his adopted daughters. Gojo immediately appoints himself the world's most annoying uncle. Geto:

“Stop giving them money.”

Gojo:

“I'm enriching their childhood.”

Geto:

“You bought Mimiko a ¥70,000 handbag.”

Gojo:

“Exactly.”

---

Yu Haibara Lives

Haibara survives his 2007 mission. The mission can still go badly, serving as another example of the incompetence of Jujutsu Headquarters, but Nanami and Haibara both make it home. That has another enormous consequence:

Nanami never loses Haibara.

Nanami can still become disillusioned with sorcerer society and temporarily leave Jujutsu High for ordinary employment, but his departure isn't fueled by the same level of grief. When he eventually returns, Haibara is there to relentlessly tease him about becoming a salaryman. ---

Kenjaku Has a Problem

This is where the “Good Ending” stops being completely peaceful. Kenjaku's plans are still happening. Yuji Itadori is still eventually born. Sukuna's fingers still exist. The Death Painting experiments still occurred. The higher-ups remain corrupt. The Zenin and Kamo Clans haven't suddenly become good people. And Kenjaku still intends to force humanity and cursed energy into its next evolutionary stage. But one gigantic piece of his future plan has disappeared:

Suguru Geto never becomes a curse user and never dies.

Kenjaku therefore cannot steal Geto's corpse. And without Geto's body, Kenjaku doesn't naturally obtain Cursed Spirit Manipulation, which was enormously useful to his canon plans. So Kenjaku begins preparing another host. ### Karin

Karin becomes the replacement vessel Kenjaku has been quietly monitoring. Instead of waiting for Geto's downfall, Kenjaku realizes something is wrong with the timeline:

Suguru isn't becoming isolated. Suguru isn't abandoning Jujutsu High. Suguru isn't forming a curse-user organization. And Suguru definitely isn't heading toward the death Kenjaku anticipated. So Kenjaku abandons him as a prospective future body and shifts his attention toward Karin. This creates an interesting butterfly effect: Kenjaku remains dangerous, but his capabilities in 2018 are different because his host doesn't automatically possess Geto's Cursed Spirit Manipulation.

He has to restructure portions of his plan accordingly. ---

2017 — Yuta Okkotsu

Yuta still becomes haunted by Rika. The higher-ups still see him as an enormous threat and initially want him executed. And Gojo still intervenes. Yuta enrolls at Tokyo Jujutsu High alongside Maki, Panda and Inumaki. But this time there are two Special Grade teachers helping him. Gojo teaches Yuta how to stop fearing his own strength.

Geto teaches Yuta about curses, emotional attachments and the relationship between love and cursed energy.

Geto is especially valuable because Cursed Spirit Manipulation gives him a completely different perspective on Rika's existence. There is also no Night Parade of a Hundred Demons. Geto never attempts to steal Rika. Yuta eventually discovers the truth surrounding Rika's curse under much safer circumstances. He releases Rika's soul while retaining his immense potential as a sorcerer. And because there is no need for Yuta's canon overseas training path, Yuta remains primarily in Japan. By 2018, Jujutsu High has an absurdly strong support network waiting for the incoming first-years. ---

2018 — The Main Story Begins

And despite everything that changed... Yuji still eats Sukuna's finger.

Megumi is sent to retrieve the cursed object. The situation spirals out of control. Yuji consumes the finger to protect people. Sukuna incarnates. For perhaps the first time, the Good Ending timeline suddenly looks frighteningly similar to canon. Except when Gojo arrives, the surrounding world is completely different. Megumi isn't an isolated teenager essentially raised by Gojo. His parents are alive. Toji knows exactly what kind of world his son has entered. Geto is standing beside Gojo rather than wearing monk robes and plotting genocide. Haibara is alive. Yuta is already available. Mimiko and Nanako aren't curse users following Geto into darkness. And when the higher-ups order Yuji's execution, Gojo isn't fighting them practically alone. Now there are several powerful adults willing to say:

No.

---

The 2018 Jujutsu High generation

Yuji Itadori, Megumi Fushiguro and Nobara Kugisaki still become first-years. Their personalities don't need to change drastically, but Megumi is noticeably different. He's still quiet, serious and prone to judging people according to whether he considers them worth saving. But he isn't carrying the same abandonment issues. And his family situation creates something hilarious for Yuji and Nobara. Because eventually they discover:

Megumi's dad is Toji Fushiguro.

Nobara takes one look at Toji. Then Megumi. Then Toji. Then Megumi again. > “THAT is your father?!”

Megumi:

“Unfortunately.”

From somewhere else in the house:

“I heard that.”

---

Toji's place in the story

Toji becomes one of the AU's biggest wild cards. He doesn't suddenly become a conventional Jujutsu sorcerer. He still despises much of Jujutsu society and has absolutely no interest in playing by its rules. But the moment Megumi becomes a Jujutsu High student, Toji starts paying much closer attention. That puts him into an extremely strange relationship with Gojo. They aren't mortal enemies in this timeline. Instead, they're two ridiculously powerful men who annoy the absolute hell out of each other. Gojo thinks irritating Toji is hilarious. Toji thinks punching Gojo through a wall should qualify as community service. Mama Fushiguro is probably the only reason Tokyo Jujutsu High hasn't needed several renovations. More importantly, Toji becomes a nightmare for the Zenin Clan. They know Megumi inherited the Ten Shadows Technique. They want him. And Toji's answer remains:

Absolutely not.

That makes Megumi's eventual relationship with the Zenin Clan much different while leaving the clan itself largely unchanged. ---

What DOESN'T Change

This is important because it keeps the AU recognizably JJK rather than creating a completely different universe. The Zenin Clan remains misogynistic, abusive and obsessed with inherited techniques. Maki and Mai's childhood therefore still occurs largely as established unless later events intervene. The Kamo Clan remains politically influential, and Noritoshi Kamo still carries the pressure associated with his family. The Kyoto students still exist and maintain essentially the same backgrounds unless one of these altered events directly affects them. The Jujutsu higher-ups remain conservative and corrupt. In fact, Gojo having Geto, Yaga, Haibara, Yuta and eventually others around him creates a much stronger reformist faction inside Jujutsu society. The history of the Heian Era remains completely unchanged. Sukuna was still Sukuna. Kenjaku still operated throughout history. Tengen still exists. The ancient sorcerers and cursed objects still exist. The Death Paintings still exist. And the foundational rules of cursed energy remain the same. So this isn't a universe without danger. It's a universe where the people facing that danger weren't systematically stripped of everyone they loved before the real battle even began.

---

The biggest theme of the Good Ending AU

The central butterfly effect isn't really “Mama Fushiguro prevents everything bad.”

It's support systems. Mama Fushiguro keeps Toji from completely self-destructing. Toji stays for Megumi. Riko's survival means Gojo and Geto aren't traumatized by her murder. Gojo remaining beside Geto helps him survive his ideological crisis. Geto saves Mimiko and Nanako without becoming their cult leader. Haibara surviving changes Nanami. Geto remaining alive changes Yuta's childhood. All of those surviving adults are then present when Yuji, Megumi and Nobara enter Jujutsu society. The curses are still horrible. The clans are still horrible. The higher-ups are still horrible. Kenjaku is still plotting. Sukuna is still Sukuna. But this time the kids don't have to deal with all of it practically alone. And that gives the title JJK: Good Ending a fitting premise:

The world didn't become kinder. More people simply survived long enough to protect the next generation.