On the verge of death, Demon Lord Clayman awakens the unique skill Regressor and finds himself 70 years in the past. He knows exactly how every alliance, betrayal and battle plays out. This time he intends to use that knowledge before Rimuru Tempest ever becomes a problem. Illustrated by Wataru Kajika. Japanese manga spin-off. Ongoing.

Read That Time I Got Reincarnated as a Slime: Clayman Revenge manga in English, updated regularly. Also known as: 転生したらスライムだった件クレイマンREVENGE · Tensei Shitara Slime Datta Ken: Clayman Revenge · TenSura Clayman Revenge