Ui Ui is a young boy with a small slender frame. He has light blue hair, styled with a neat left-sided part and thin eyebrows. Ui Ui wears a white long-sleeved jacket similar to the Jujutsu High uniform. He also sports suspenders, black shorts, long socks, and simple shoes. Ui Ui is a mature and proper young man who really doesn't display any typical traits for someone his age. He's defined by his loyalty and devotion to his sister, Mei Mei. (he talks about Mei Mei a lot.) He is 12 years old.