Kasai is kinda tall for his age, and has a muscular build. Kasai has snow-white hair (doesn't look like it in the picture cuz of the lighting) which is very spiky, and pupiless purple eyes. He tends to wear a simple black tank-top, along with black shorts, with wrappings on his lower legs. He doesn't wear his shinobi headband, and also doesn't use a shuriken holster. Kasai wears black sandals as well.
Kasai is a very stoic, and often times sarcastic person. He doesn't speak all that much, and usually doesn't talk to anyone unless they talk to him first. The exception to this is if he's around his friends, in which case he talks quite frequently and has no problem starting conversations. He jokes a lot, but rarely means any offensive things he says.