Haruki Hayashida, known as Pah-chin, stands as a founding member of the Tokyo Manji Gang and its Third Division Captain. His short, stocky frame features bleached hair parted to the right with shaved sides, a small stitch on his lower lip, and a scar under his left eye. He wears the Toman uniform during his gang tenure, later adopting formal attire.

Pah-chin readily admits his lack of intelligence, a point noted by peers like Ryohei Hayashi, sometimes using it to excuse impulsive actions. Yet, he possesses fierce loyalty, especially toward Mikey, whom he deeply respects. This protective nature surfaces when Moebius assaults his girlfriend and friend. Initially suppressing his desire for revenge to protect Toman, he ultimately confronts their leader, Nobutaka Osanai, in a duel. Overpowered by Osanai's boxing skill, Pah-chin stabs him and accepts arrest to shield his comrades, resulting in a two-year detention.

Upon release, he reclaims his role as Third Division Captain, demonstrating significant personal growth. He establishes a real estate business, revealing unexpected professionalism and attention to detail that leads to commercial success. His post-detention life reflects a more focused demeanor while retaining his core traits.

He owns a dog named "Pochi," harbors a fear of cockroaches, and admires tigers. Among peers, he ranks first in arm wrestling proficiency and holds the highest scores on punching machines.

In combat, Pah-chin ranks among Toman's strongest brawlers according to Peh-yan. His exceptional durability allows him to endure severe beatings, even Mikey's signature kick, and remain conscious. However, his straightforward fighting style leaves him vulnerable to technically skilled opponents like Osanai.