My Brother Is Hard to Handle [Anime Crossover]

Quick transmigration into anime worlds, becoming an older brother and saving people's lives.

Choose whichever anime world you like. The different worlds are mostly unrelated.

In the One Piece world, Su Yang transmigrates as a baby, is found by the bandit Dadan, and becomes the older brother of Luffy and his two brothers. Unlike Luffy and the others, Su Yang has no interest in pirates and instead joins the Marines. Although he transmigrated, he doesn't awaken memories of his past life in the One Piece world. (Complete)

In the Attack on Titan world, he awakens memories of Earth and becomes Eren's twin brother. (Complete)

In Bungo Stray Dogs, he becomes Chuuya Nakahara's older brother. (Complete)

In Naruto, he becomes Itachi's twin brother. (Complete)

In Jujutsu Kaisen, he becomes Yuji Itadori's older brother. (Complete)

In Demon Slayer, he becomes Muzan's older brother. (Complete)

In Shiki, he becomes Natsuno Yuuki's older brother. (Complete)

In Detective Conan, he becomes Gin's older brother. (Complete)

In Parasyte, he becomes Shinichi Izumi's older brother. (Ongoing...)

In Assassination Classroom, he becomes Koro-sensei's older brother.

In Western fan fiction, he becomes the Joker's older brother.

In Death Note, he becomes Light Yagami's older brother.

In Black Butler, he becomes Ciel's older brother.

In Overlord, he becomes Satoru Suzuki's older brother.

In Bleach, he becomes Ichigo Kurosaki's older brother.

In JoJo's Bizarre Adventure, he becomes Yoshikage Kira's older brother.

In Hunter x Hunter, he becomes the eldest son of the Zoldyck Family.

In Tokyo Ghoul, he becomes Ken Kaneki's older brother.

In Fate/Zero, he becomes the older brother of Gilgamesh and Kiritsugu Emiya.

In Vinland Saga, he becomes Thorfinn's older brother.

In Tokyo Revengers, he absolutely has to save Baji.

In Danganronpa 3: Despair Arc, he becomes Nagito Komaeda's older brother.

In Natsume's Book of Friends, he becomes Takashi Natsume's older brother.

In Dr. Stone, he becomes Senku Ishigami's older brother.

Theme: Save Ace, Sasha, Commander Erwin, Oda Sakunosuke, Itachi, and Nanami