Kasu has short brown hair with bangs. He wears a simple black collar shirt underneath a gray cardigan. He wears gray jeans and black slip on shoes. He carries a silver pocket watch with a chain that isn't worn in his cardigan pocket. He has brown eyes.
Kasu comes off as a polite person that is a realist and thinks about many possibilities that could happen, and is often very worried about many things as a result. Kasu was scouted as the ultimate insulter due to be seen having in many verbal arguments. Kasu hides his true ultimate talent because he worries about his social life and people not liking him because of his actual talent. He thought of the ultimate lip sync because he thought it was a realistic and simple talent. Kasu's personality is shown to be a lie and is actually a low tempered, random, and having no remorse to his actions, and seems to be the type of person who goes big or goes home.