Numbuh 84, or Lee, is a 7 year old boy who attended KND training academy with Sonia and Tommy in Operation: T.R.A.I.N.I.N.G., and later became the "Tactical Yo-yo Specialist" of Sector W. He usually wears a blue and orange striped shirt, blue shorts, brown shoes but with no socks and a brown ushanka that covers his eyes. Lee constantly uses the word "cool", saying it multiple times in almost every episode in which he appears, although his vocabulary is far from limited.