Jujutsu Kaisen is owned by Gege Akutami / Shueisha / MAPPA.Fullmetal Alchemist (FMAB) is owned by Hiromu Arakawa / Square Enix / Bones.Marvel and the Super Soldier Serum are owned by Marvel Comics / Disney.
I do not own any of these characters, settings, or franchises. This fanfiction is written purely for entertainment purposes, and I am not making any money from it. No copyright infringement is intended.
Please read the Tags before starting to read the story.
I really love the power system in JJK, so I'm going to be as faithful to it as I can. The MC is going to be very powerful, but he will have to put in a lot of work to reach Gojo/Sukuna levels. All power-ups will be earned. This is AU so there will be changes like Jujutsu high starting at age 16 etc. I will build more lore around Jujutsu that are consistent with what Gege has written.
The MC is reincarnated, meaning he is a child with adult memories—not an adult in a child's body. This is not a transmigration story. The MC has no canon knowledge, so this is a true isekai story where he discovers the world for himself. His memories from his previous life are hazy, and he only regains them over time. This will play an important role in the story.
Before reincarnation, the MC was gifted the Super Soldier Serum by ROB. This is the serum from the Marvel 1610 universe—Ultimate Captain America, not MCU Captain America.
The serum boosts the MC's brain, body, and reflexes. His lifting strength will be around 5–10 tonnes, and he will have extremely fast processing speed and reflexes. The serum only enhances his body—it does not give him cursed energy. For comparison, Toji should be over 100 tonnes and much faster.
The MC has very high cursed energy reserves, around 15-finger Sukuna, and he also has very high cursed energy output. His cursed energy is so high because he reincarnated with the soul and memories of his previous life. MC will look like Roy Mustang from FMAB but more muscular because of the serum.
I will try my best to ensure that all changes fit within the JJK power system.
The MC's cursed technique is inspired by a mix of Roy Mustang and Kimblee from FMAB.
If you are a very politically correct person, this fanfic is not for you. Most of the strongest JJK sorcerers are weird—the MC is no different in that regard.
Mei Mei is Mei Mei, so consider that a warning.
The Zenin clan is also a bunch of inbred hicks, so keep that in mind too.
The super soldier serum enhances pre-existing personality traits. Steve Rogers was a good man, so it made him great. The MC is not, so it will exaggerate his pre-existing tendencies.
The MC and other characters will make assumptions based on the knowledge available to them—this is intentional. The MC will be very powerful, but he will still make mistakes that are consistent with his character. Please understand that the characters in this story do not have the knowledge that you, as the reader, have. MC will be born a few months younger than Maki and Mai.
This is JJK so expect some fucked up stuff to happen, There will be some R18 scenes. They will be marked and are skippable. So buckle up and lets enjoy the ride !!