Sen is a young man of medium height with dark, shaggy hair and dark eyes, which are relatively thin and lazy-looking. He has a modest athletic build, the same as most of his classmates, and a slight tan. Sen is a levelheaded person who remains mostly calm and focused on many occasions. He is also shown to be more mature than Neito Monoma, telling the latter to quit provoking Katsuki Bakugo and focus on his goal during the Cavalry Battle.