Numbuh 274

Numbuh 274 was, according to legend, the greatest KND ever until he betrayed the Kids Next Door.

Family
We know Numbuh 274, A.K.A. Chad Dickson, has a mother and a father, who are known as Mega-Mom and Dyno-Dad. They are the two worst villians the Kids Next Door have ever encountered. In fact, they froze every member except Numbuh 274.

Kids Next Door
We know, like most operatives, Numbuh 274 went to the KND's Anarctic training base. According to Operation E.N.D., he run the show there. Then he graduated and started working his way up quickly through levels of KND promotions. Eventually, by age 13, he was Supreme Commander of the KND.