Goto Imasuji, also known as Muscular, later Jailbreaker, is a villain affiliated with the League of Villains as part of its Vanguard Action Squad. He serves as a primary antagonist of the Forest Training Camp Arc.

He was incarcerated in Tartarus, being freed by All For One. until he was once again defeated by Izuku Midoriya and imprisoned.

Goto is a large, bulky, and extremely muscular man set wide with short, spiky, and sandy blond hair with small black eyes. He has a large scar going across the left side of his face, his left eye replaced with a prosthetic one, and he has another, smaller scar on the right side of his forehead. As of his appearance after the Paranormal Liberation War, Goto’s hair has grown longer and he has developed stubble all over his chin.

His outfit consists of a black, hooded cloak and a white hockey mask with multiple holes. Underneath this, he wears a red tank top, a dark jacket that hangs around his waist, dark green pants, and black knee-high boots.