Retsu Kaioh is getting isekai’d on television. TMS Anime announced a TV adaptation of Baki Gaiden: Retsu Kaioh wa Isekai Tensei Shitemo Ikko ni Kamawan, the spinoff about the kenpo master waking up in another world after Musashi Miyamoto killed him.
The English title some outlets are using is Baki Side Story: Kaioh Retsu Doesn’t Mind at All If He Gets Reincarnated in Another World. That is the whole joke and the whole pitch. Retsu dies in the mainline fight with the swordsman, then treats a second life like another venue. Check out the teaser trailer below:
Eiji Mutsui draws the manga. Keisuke Itagaki is credited for the original concept. Sai Ihara, also listed as Daisuke Ihara, has the story credit. It launched in Akita Shoten’s Monthly Shonen Champion in 2020. Volume 1 shipped in May 2021. Volume 16 landed March 6. Volume 17 is due September 8. Print and digital together have passed 2 million copies.
TMS is the studio name working on the anime, the same company tied to the Netflix Baki run, including Baki-Dou: The Invincible Samurai, which dropped its first cours all at once on February 26 and its second 12 episodes on June 18. No director, series composition, or cast list came with this particular drop. Some reports put the isekai series in 2027. TMS has not posted a broadcast season or episode count on the ANN writeup.
A stage version is already dated. Baki The Grappler STAGE Gaiden of the same Retsu story runs March 19 to 22, 2027 at Owl Spot in Tokyo’s Toshima Ward. The play and the TV show are separate productions of the same manga.
Itagaki’s main Baki The Grappler manga ran 42 volumes in Weekly Shonen Champion from 1991 to 1999. The sequels kept coming: Baki for 31 volumes, Hanma Baki for 37, the first Baki-Dou for 22, a second Baki-Dou from 2018 to 2023, and Baki Rahen from August 2023. Kodama Tales started English editions of the original in October 2025. Media Do handles later books. Netflix has been the worldwide home for the modern anime since 2018.
Retsu is one of the franchise’s cleaner fighters, a Chinese kenpo specialist who treated grappling arenas like a classroom until Musashi cut that short. Dropping him into a fantasy isekai is an interesting use of a character who already solved problems with technique instead of shouting. The manga title says he does not mind however. The TV show has to make that attitude play for people who only know Baki from the Netflix fist fights.
Staff beyond TMS, a network, and a first-air month are still missing so we wont know those yet. Until those show up, the news is the adaptation itself, the 2 million copy count, and a March 2027 stage date that may or may not line up with the anime.
Are you watching Retsu’s isekai run, or is Baki the only underground arena for you to watch? Let us know your thoughts in the comments below.