Wallabee "Wally" Beetles a.k.a. Numbuh 4 is the brash and impulsive hand-to-hand combatant Australian boy of the Kids Next Door Sector V. He is close friends with Hoagie and has a crush on his teammate, Kuki, who is his close friend and teammate who returns his feelings. He ends up marrying Kuki in the future. There are few amongst the KND that can match him in hand-to-hand combat, and even fewer who can compete with his bravery. Numbuh 4 is also known for his apparent lack of intelligence, preferring to simply beat up any and all obstacles in his way.
Wally is a 10-year-old boy with blond hair in a bowl cut. He wears an orange hooded sweater, blue jeans and white sneakers. His eyes, like almost the entire Sector V, are not always visible, although it is later revealed that his eye color is green. He is also the shortest Sector V member, for which he is picked on a lot (for example, Abigail called him "sport" in Operation: M.A.T.A.D.O.R.). He speaks with a Broad Australian accent.
