Tsukasa Shishio is a towering figure of unparalleled physical prowess, often referred to as the "Strongest High School Primate." He possesses a complex duality: a ruthless destroyer of petrified adults, driven by a vision to create a purer, uncorrupted world, and a deeply compassionate protector, especially towards his beloved sister, Mirai. His charismatic leadership and unwavering moral convictions make him both a formidable antagonist and a sympathetic, multifaceted character in "Dr. Stone."