Tsukasa Shishiou is a pivotal character in the anime series Dr. STONE. Known as the 'Strongest High School Primate', he is a formidable fighter with a strong sense of justice. Tsukasa plays the role of the main antagonist in the initial arcs of the series, opposing Senku Ishigami’s vision of reviving civilization. He advocates for a world where only the young and pure-hearted are revived, aiming to create a new world free from the corruption of the old. Despite his antagonistic role, his actions are driven by a desire to protect innocence and purity.