Fist of the North Star Side Story: The Genius Amiba’s Otherworld Conqueror Legend is a spin-off manga that has rarely disappointed. Its silly premise is that the minor villain Amiba (aka Fake Toki) has been isekai’d, only rather than getting killed by a truck, it was death by Kenshiro. And instead of getting run over, it was being violently exploded while forced to walk backwards off a ledge.
Amiba is a delusional asshole who has noteworthy skill but frequently overestimates himself. He is devoid of honor and compassion, and cares little about anything but showing what a “genius” he is. It’s why he’s such an insufferable enemy in the main series, but the funny thing is that the guy’s poor personality results in a manga with a much more balanced roster of good guys when he’s the lead.
In the original Fist of the North Star, Kenshiro is a perfect hero to a fault. He’s great for his story, but he also always overshadows his allies because he’s the strongest, kindest, and most badass guy around. A similar thing happens with other spin-offs: Whether it’s Raoh, Toki, or whoever, they’re often portrayed as being a level or ten above those around them. Not so with Amiba.
In the new world he finds himself in, Amiba has little natural aptitude for the sorcery inherent to it. But while his Hokuto Shinken skills are woefully incomplete compared to the true masters of his original life, such martial arts skills are virtually unheard of in the other world. Many characters outclass him in a few (or many) ways, and it means that Amiba can’t do everything on his own despite thinking he can. As the roster of allies (all of whom are parodies of existing FotNS characters) grows, they function much more as a team than Kenshiro and friends ever did. Whether it’s Toluukin the great mage (Toki), Shuuza of the Clouds (Juuza), or a gigantic grandma (who is actually not an oversized goon in disguise but rather the headmaster of an elite wizard school), everyone shores up the others’ weak points.
It’s great. Amiba makes for a fun main character because he’s so utterly flawed. The series doesn’t celebrate that fact—more using it as the basis for its humor—but it also provides plenty of opportunity for growth to an extent. At the end of Volume 7, Amiba is outnumbered against the Demon Lord’s army. Defeating them would be impossible, but then all the people he met in this other world appear, ready to help him (think Lord of the Rings: The Two Towers or Avengers: Endgame). In response to the overwhelming support, Amiba talks about all he sees around him are idiots, but that together, they can accomplish what average nobodies never could—that collectively, they are geniuses.
Amiba is still the height of arrogance and selfishness, but now he’s extended that attitude to include all his allies. He won’t ever be the hero Kenshiro is, but he can make a difference in his own way (if he can manage to get over himself).