The Teen Ninjas are a faction of teenagers equipped with Battle Ready Armor, lead by The Steve. They've also worked with other villains, such as the Delightful Children From Down The Lane, and Father. The two most notable members are Cree Lincoln and Chad Dickson, both former KND operatives, who frequently lead them in their battles. This faction also has many other fugitive KND operatives who have escaped decommissioning when they turned 13.
In Operation: S.L.U.M.B.E.R., a group of ninjas hired by Father attempted to make off with the Code Module being led by Cree; Chad was keeping Numbuh 86, Numbuh 23, Numbuh 12, Numbuh 3, and Numbuh 4-30teen-7 busy and away from the Moon Base by disguising himself as Numbuh 86's mother and making her throw a slumber party. It might have worked if not for Numbuh 4's uninvited presence.
In Operation: T.R.E.A.T.Y., it is revealed that their leader is a boy named "The Steve". Like most teenagers, Teen Ninjas members are fond of torturing children in general, but most of their proper operations consists of attacks on the Kids Next Door organization.
The first episode to feature multiple Teen Ninjas was Operation: L.E.A.D.E.R.. In this episode, Chad refers to his group as "The Jets".
However, there are other undercover operative agents still working for KND, the most notable being Maurice and Chad himself.They are secretly infiltrating the Teen Ninjas to leak secret Teen information to KND Global Command without the other Teen Ninjas knowing.