Yi has a feline appearance, which is a common trait among the Solarians. He has a creamy fur, a round head, pointed ears, and two tufts of fur on the sides of his face, as well as a small triangular nose. He has large almond-shaped eyes with large black pupils and no visible iris. His mouth or eyebrows are not visible, but he mainly expresses his feelings by opening his eyes or frowning. His hands look like human hands, with fingers ending in claws instead of nails. He wears an outfit consisting of a black bodysuit, black shoes with white socks, and a long, free-sized yellow hanfu robe with the Sun and Fanshi symbols. He is shorter compared to other characters and has a jade ring-shaped device on his body that stabilizes the heart. These features are related to an accident that nearly cost him his life in his youth. In his childhood, he wore a chiroko-blue Chanshan (Chinese-Manchu traditional clothing), and the fur tufts on his face were also noticeably smaller. After becoming Eigun's disciple and joining the Tiandao Council, he began wearing deep chiroko-gray Chansan and chiroko-blue Magu decorated with a Norigé with the council symbol, although his hanfu robe was deep chiroko-blue during his time as a council member.