Ren Nikaidou

Ren Nikaidou is Satou's primary rival and the one responsible for inventing and spreading Satou's infamous nickname. While he lacks a title of his own, his strength is undeniable. He initially sides with Endo to oppose Sen and Yō, but his loyalties shift when he later attempts to negotiate peace with Endo. Beyond his combat abilities, Ren harbors a clear romantic interest in Matsuba.