Knightbrace, real name Mr. Jelly, is a recurring antagonist of Codename: Kids Next Door. He is an oral health-themed villain who attacks children at night and forcibly performs painful and unnecessary dental and orthodontic procedures on them. He is one of the most frequently recurring villains of the series alongside Toiletnator, Count Spankulot, and Stickybeard.
Knightbrace's true identity is Mr. Jelly. Mr. Jelly had dreamed of being a dentist all his life, but used extreme methods and was kicked out of dental school for trying to put braces on babies. He was then forced to work in his family's candy store, thus damaging kid's teeth rather than cleaning them. This ultimately drove him over the edge. He thus became Knightbrace and sought out to repair the damage he'd done. Knightbrace wears a dark blue/purple costume with a tooth on the front and a large halo-shaped retainer; this causes him to speak with a lisp. He also wields an extremely large toothbrush, clubbing the Kids Next Door with it and even using it to pole vault. He considers himself to be a vigilante similar to Batman, styling himself the Enamel Avenger.
Codename: Kids Next Door
Knightbrace first appeared in Operation: T.E.E.T.H.. Sector V first became aware of Knightbrace when he was encountered by Numbuh 3 while she was walking home one night after a trip to Mr. Jelly's candy store; the entire team went back to the candy store with her because her teeth got whitened to an extreme level. On the way back, Knightbrace launched a sneak attack on Numbuh 4 and nobody noticed until they reached the Sector V Treehouse, whereupon they found Numbuh 4 tied up with giant braces that stuck out very far and within minutes both Numbuh 2 and Numbuh 5 were also attacked and tied together with floss. The KND initially assumed him to be Dr. Sigmund Teef, a dentist who had offered them free checkups (and been rudely refused) earlier that day. When the villain is unmasked by Numbuh 1, he and his team are shocked to learn his true identity to be Mr. Jelly. Dr. Teef, who had been awakened by the noisy fighting, then walks into the room, at which point Knightbrace's past is revealed. Dr. Teef saves the KND from Knightbrace by giving him taffy, his "delicious weakness". Apparently, even Knightbrace has an occasional sweet tooth, despite his hatred of cavity-inducing foods.
In Operation: F.L.U.S.H., Toiletnator believes Knightbrace to be Numbuh 4, who he considers to be his arch-nemesis, when he attacks his fellow villains at the Sector V Treehouse and violently disposes of him. When he does this to Knightbrace, a view of the treehouse shaking violently is shown on screen with a rumbling sound affect.
In Operation: A.W.A.R.D.S., Knightbrace is the host of the Villain's Choice Awards. As his clothes are stolen by Numbuh 4 during the episode, he is forced to appear onstage in his underwear. He was to read the winner of Best Villain award, but was caught up in the fighting before it could be revealed.
In Operation: I.N.T.E.R.V.I.E.W.S., Knightbrace is believed to have been tie-ified by a Queen Neck Tie along with Potty Mouth while at the tieland common shopping mall. It's unknown what happened to him after this, mostly he either got eaten alive or more likely he was tie-ified and it is not confirmed if he and Potty Mouth will return back to their normal selves.
- Even though Knightbrace's secret identity wears glasses, they are not visible at all when he is in his alter-ego.
- It's possible that when he is in his alter ego, he wears contact lenses, or his glasses are decorative.
- Additionally Knightbrace's eyes are visible while he is in his alter-ego, but they aren't visible in his secret identity.
- Knightbrace and Count Spankulot are the only villains who appear as vigilantes that attack children at night.