Ongakuya Ishinō is a hero in the anime Scum of the Brave, a government-sanctioned fighter operating in the criminal underworld of mid-21st-century Tokyo, where heroes use ether-based abilities to hunt the gang leaders known as Demon Lords. He is a male combatant who goes by the ominous alias Music Man, a name that captures both his refined bearing and his unsettling bond with sound. His reputation mixes elegance, mystery, and outright menace: he presents himself with polish and composure, yet those around him sense a volatile and dangerous presence. He is regarded as a highly dangerous fighter, and his relationship with death is as unusual as his relationship with music, two themes that define his identity.

In the early events of the story, Ishinō is one of the people the protagonist Yashiro seeks out at the bar run by Ed, where he appears alongside the hero known as Salt Joe. He belongs to Yashiro's circle of contacts within the hero underworld, and his standing there is that of a companion, but one with a fearsome edge. He is known as the most dangerous friend, a label that reflects both his closeness to Yashiro and the threat he carries. Beneath his composed surface runs a current of madness, matched by extraordinary supernatural powers, and his combat ability is inseparable from the music-themed identity he cultivates, with sound serving as the medium of both his style and his menace.

Ishinō's role in the narrative is shaped by his place at the edges of Yashiro's world: he is an ally who can be called upon in the escalating confrontations between heroes, Demon Lords, and criminal organizations, yet his presence always carries an undercurrent of peril. His loyalty does little to soften the unease he inspires, and he embodies the series' recurring idea that the heroes who police Tokyo's underworld can be as frightening as the enemies they are hired to eliminate.