Charanko is Bang's only and last disciple before he was recently "expelled" for some reason that is anything to do with his master and his former number 1 disciple, Garou.

Charanko is a loudmouthed braggart, arrogantly challenging Saitama and Genos for their disinterest in Bang's martial art without knowing of their ability. When Saitama comments on Bang's strength, Charanko speaks out again, eagerly describing his master's martial arts ability as well as his hero rank, only to be quickly silenced by his master's reprimand. Upon finding out why his master "expelled", but ignore his warning, Charanko has a sense of martial art's honor towards any fellow Dojos in which his former fellow disciple, Garou destroyed.

Sound like a naive and arrogant young man.He is more bark than bite, so sound like an arrogant tough guy at the start, but then a weakling on the third line.