The split-chinned kid (アゴの割れたガキ) is the grandson of Agoni, a multi-millionaire and the founder of the Hero Association. He was saved by Saitama from three years prior to the start of the series..
The split-chinned kid is largely characterized by his enormous cleft chin. He is a young boy with short black hair. He wears a white T-shirt with orange shorts and blue sneakers.
He seem to be mischievous, drawing nipples on Crabrante's chest while he was asleep in the park.
He was first seen playing with a ball at the park, until Saitama came and questioned him about Crabrante. Suddenly Crabrante appears and attacks him, but Saitama protects him.
One-Punch Man Manga; Chapter 2, page 6-15