Hokuto no Ken Gaiden: Tensai Amiba no Isekai Haou Densetsu  

A Genius Isekai Overlord Legend: Fist of the North Star Amiba Gaiden - Even If I Go to Another World, I Am a Genius!! Huh? Was I Mistaken..., Hokuto no Ken Gaiden: Tensai Amiba no Isekai Haou Densetsu - Isekai ni Ittemo Ore wa Tensai da!! n!? Machigatta ka na..., 北斗の拳外伝 天才アミバの異世界覇王伝説

In this separate comic book series, we encounter Amiba, an exceptionally skilled fighter with an unparalleled ability to master any combat technique rapidly. Despite his impressive talents, he is ultimately bested by the main character from the initial series, Kenshirou, and passes away. Subsequently, he finds himself transported to a new realm where he embarks on a fresh journey.