Satoru Gojo has a younger sister. He’s been raising her since she was 4 and he was 17. Their parents abandoned both of them because they believed they were too strong and dangerous.
After the death of Junpei Yoshino by Mahito, where Yuji tried to save him, Junpei’s twin sister reluctantly joins Tokyo Jujutsu High. She’s a sought after Special Grade Sorcerer who believes in saving lives and purifying the world with love and light. She’s never been a full sorcerer. She was just a healer that was called upon when needed. But, now, she’s joining Tokyo Jujustu High to get and save as many people as she can.
A year after Yuji Itadori, Megumi Fushiguro, and Nobara Kugisaki entered Tokyo Jujutsu High, Gojo discovers an unfamiliar girl living alone on the streets. She’s exhausted, injured, and clearly hasn’t been taking care of herself. But there’s something strange about her. Even while unconscious, an enormous amount of positive cursed energy is radiating from her body. Gojo immediately realizes that this isn’t an ordinary civilian. She’s a potential Special Grade. Nobara, Megumi, and Yuji see Gojo carrying her into the school grounds as he’s taking her to his quarters to get her cleaned up. They’re all worried, but Yuji is automatically protective and in a trance because of Sese. When he actually gets to meet her he falls in love with her instantly. He becomes slightly obsessed, possessive, and protective.