Class seat number: 12

He is a student of Kunugigaoka Junior High School. He is assigned to Class 3-E, where he trains to become a professional assassin, with his teacher as the target.

Sousuke is exceptionally skilled at drawing and sculpting. His proficiency ranges from posters to disguise masks; he can make them with relative ease. He is also strongly individualistic, and launches attacks against Korosensei in a capricious, unpredictable manner; for instance, he offers to draw a Henna tattoo on Korosensei, but secretly had the Anti-Sensei bullets grounded into a fine powder and then mixed with the Henna paint.