"Gee, you guys are even touchier than Sector N!" -Numbuh 13, to Sector V.
Numbuh 13 is a very unlucky and incompetent operative who causes disaster wherever he goes, hence his name, to the point that he is avoided by all other operatives, including his own teammates. He is completely oblivious to the fact that nobody likes him, and is overly eager to jump into action even if doing so directly goes against orders. He also seems to believe that the unlucky things that happen around him aren't his fault, and always blames someone else when something goes wrong because of him.
He was introduced in Operation: M.A.C.A.R.R.O.N.I., where a prisoner exchange between the KND and Mr. Boss's group occurs involving him and the Toiletnator. As they go back to where Numbuh 13 lives to return him to his sector, he warns them that the adults are planning to have macaroni for dinner, which poses no apparent harm whatsoever and is ignored by the others.When they learn that they are getting their macaroni from the "Rainbow Monkey Lisa" they head to the Macaroni Museum of art to stop them. Once there, Numbuh 13 completely ruins the mission, destroying a Rainbow Monkey vase as well as the Rainbow Monkey Lisa, and being inadvertently recaptured by the villains by hiding himself in their bag, which the others are actually glad of.
In Operation: I.T., he is buying a hot dog when he is made "It" and will become Supreme Commander. He is the only one who appears to be happy about this even though everyone is trying to avoid becoming Supreme Commander. Numbuh 13 is immediately dogpiled to the ground by everyone else in the area, who would rather risk being it when the game ended and becoming the supreme leader than let Numbuh 13 be in charge of the entire organization.
- Numbuh 13 is very unlucky as the number 13 is often considered an unlucky number.
- Possibly, his codename number may correspond to the the unlucky operatives who turn 13 who get decommissioned.
- Nobody wants him to be Supreme Leader of the Kids Next Door because of his bad reputation and would risk anything to be tagged so Numbuh 13 won't be their new leader.
- He is the most disliked operative in the KND due to his clumsiness, with Numbuh 363 being second.