The Shibuya Incident puts many of our favorite Jujutsu Kaisen characters in some of the highest stakes circumstances they have ever been in thus far, especially those who are undergoing a possible promotion to First Grade. That being said, although the arc mostly includes both sorcerers and curses we have grown to know in Season 1, it also introduces a few new characters. One of these new characters we meet during the latter part of Season 2 is First Grade sorcerer Mei Mei’s little brother Ui Ui, who has to be the youngest human to be stepping inside the veil and partaking in the events of the Shibuya Incident Arc.
Introducing Ui Ui
Ui Ui first appears in Season 2 Episode 8 – the 32nd overall – or Chapter 83 of Gege Akutami’s manga. When he’s introduced, he’s with Mei Mei and Yuji Itadori at Aoyama Cemetery, prior to them entering Meiji-Jingumae Station. From the get-go we see that he has a bit of an obsession over his elder sister, seemingly content in doing her every bidding, even going to the extent of laying a handkerchief down for her to sit without her having to ask him to. Ui Ui is as devoted to his older sibling as Mei Mei is motivated by money.
The way he acts and views Mei Mei is reminiscent of how Yushiro behaves around Lady Tamayo in the Demon Slayer series, also bearing the characteristic of being far more unpleasant to other characters – the protagonists in both instances – than to the object of their undying admiration. Not only is Ui Ui rude to Yuji, but he’s also disdainful of someone like Satoru Gojo for “forcing” his sister to be his backup. When Mei Mei tells him that the special-grade sorcerer shouldn’t be treated “like some ordinary man,” Ui Ui protests that she’s not ordinary either. He’s also seemingly unbothered by the fact that his sister values money, or “work relationships,” more so than family.
Ui Ui is voiced in Japanese by voice actress Yuko Sanpei, a professional in the industry since the year 2000 who has a generous repertoire of male roles under her belt, including anime protagonists such as Boruto Uzumaki, Taichi Yagami, and Tsubasa Ozora.