This article focuses on the relationships between Numbuh 1 and other members of the show.
Family
Monty Uno (Numbuh 0)
- "Dad...you ARE Numbuh 0... Oh, my gosh! I can't believe it! I can't wait to tell everyone! They'll be like, "You're the coolest, Numbuh 1!", and then I'll be like, "Yeah, I am, aren't I?". And then we'll go on missions together and battle evil adults and AHHH!!! My own dad is really Numbuh 0!" - Numbuh 1 after discovering that his father is Numbuh 0 in Operation: Z.E.R.O.
Monty Uno "Numbuh 0" is Numbuh 1's dad. He's famous for bringing the KND to its seventh age. During Operation: O.O.M.P.P.A.H., Numbuh 1 is embarrassed that he's his dad however towards the end of the episode, he fights for his dad back from Willard (a lonely kid who wants his own dad to pay attention to him). Then, this changes the relationship between Numbuh 1 and Monty as he takes up playing the sousaphone (not tuba).
In Operation: E.N.D., Numbuh 1 takes the opportunity to spend some quality time with him though it changes when Numbuh 86 and her decomissioning squad chases them. Later in that same episode, he mourns about how he wanted to spend quality time with him.
Numbuh 1 and Monty in Operation Z.E.R.O..
Everything starts to change during Operation: Z.E.R.O. when Numbuh 1 first yells at him to shut up because Monty only babbles on about spending quality time as he's oblivious to what's happening around them (even when they're being chased by Citi-zombie Hamsters). Once Numbuh 1 uses the recomissioning device on his dad, he instantly becomes Numbuh 0 once again, leading to Numbuh 1 spazzing as he can't believe that his own dad is Numbuh 0.
The two go out of their way to defeat Grandfather and save the entire world. At the end of the movie, Numbuh 0 gets decomissioned along with Grandfather. Numbuh 1 tries to figure out what's wrong with the recomissioning device though he gets a message that he shouldn't recomission Numbuh 0 because his greatest mission is "Being a good father to my son Numbuh 1.". This makes him cry and Monty coming up from behind and asking what's wrong. Numbuh 1 hugs him and tells him it was just an old friend.
In Operation: I.N.T.E.R.V.I.E.W.S., Monty becomes Numbuh 0 one more time along with his wife, Numbuh 999, to wish him off and tell him that he's proud of him to become the first Earth representative operative of the Galactic Kids Next Door.
Mrs. Uno (Numbuh 999)
- "You were in the Kids Next Door, too?!" - Numbuh 1 in Operation: I.N.T.E.R.V.I.E.W.S..
Numbuh 999 is the wife of Monty Uno and mother of Numbuh 1. Not much is known about their relationship to each other, but she seems to be a decent British woman who does everything a mother should do for their son. In Operation: I.N.T.E.R.V.I.E.W.S., she reveals that she is proud of her son accomplishments and wishes him a best journey in the Galactic Kids Next Door.
Numbuh 10
"And I think this is the first time I'm actually relaxing a bit instead of constantly thinking about missions and stuff." -Numbuh 1 in Operation: H.O.L.I.D.A.Y. In Operation: H.O.L.I.D.A.Y., Lizzie suspects that Numbuh 1 is cheating on her with Numbuh 10 and arrives at Sector J with Numbuh 2 and Numbuh 3 in tow. Numbuh 1 and Numbuh 10 tell her that they aren't dating, but that Numbuh 10's father is his mother's long-lost brother, making them cousins.
Love Interests
Lizzie breaks up with Numbuh 1 in Operation: G.I.R.L.F.R.I.E.N.D.
Lizzie Devine
Lizzie was Nigel's girlfriend for almost the entire series until Operation: G.I.R.L.F.R.I.E.N.D. where they split up. In episodes with her, he's always looking out for her even when she's driven him to the point of madness such as Operation: L.I.Z.Z.I.E. where she puts a boyfriend helmet so that he would pay more attention to her.
In Operation: D.A.T.E., it can be inferred that when he was still together with her, and must have spent quality time with her due to all of the myriads of pictures she had of him or where they were together. However he is usually too busy with the KND to go on a date, which is frusturates Lizzie. Though, in Operation: S.N.O.W.I.N.G., he had to save her from being the President's girlfriend. The two are also shown to be very close in Operation: P.O.O.L..
However, in Operation: G.I.R.L.F.R.I.E.N.D., the relationship is hinted throughout the episode to the end that it will end. Lizzie realizes that, after Nigel saves her from the Treehouse, she can't compete with the Kids Next Door anymore and she wants a boyfriend who is willing to pay more attention and love towards her. Numbuh 1 tells her not to go away though she goes away leaving him to shed a tear at the end of the episode.
It seemed that even though they were together at a long time, their relationship cannot work out since she wanted Numbuh 1 to turn his back on missions for a date. Even though Numbuh 1's purpose was for the KND. He could only be with someone who understands his passion.
Friends
Numbuh 362
Numbuh 1 and Numbuh 362 after the events of Operation: G.I.R.L.F.R.I.E.N.D.
Numbuhs 1 and 362 are seen to be very close throughout the series, as they call themselves by their first names. In Operation: I.T., they are shown working together to reclaim the KND from Father. At the end of Operation: Z.E.R.O., they are seen casually talking with one another. The two are seen having lunch together in Operation: G.I.R.L.F.R.I.E.N.D.. When Lizzie breaks up with him, Rachel tries to cheer up Numbuh 1. Numbuh 362 has a high opinion of Numbuh 1's sector.
Numbuh 6 (Bradley)
In Operation: C.A.M.P. when Numbuh 1 saw Bradley, he said that they didn’t have time for babies and called Bradley stupid and hurt his feelings but took it back after Bradley and his parents saved everyone from being brainwashed by Chester and Numbuh 1 gave Bradley a medal and became Numbuh 6 and got sprayed by Bradley to show affection to Numbuh 1, who became Bradley’s friend and babysitter.
Numbuh 5
Numbuhs 1 and 5 are close friends and Numbuh 5 is like a big sister to Numbuh 1. In Operation: U.T.O.P.I.A., she is concerned with his safety after contact was lost with him. They, in Operation: L.I.C.E., are the last remaining two in the Cheese Room. In Operation: I.N.T.E.R.V.I.E.W.S., Numbuh 1 compliments Numbuh 5, saying she's the only one in the sector with any real common sense and handed his glasses over to Numbuh 5.
Numbuh 4
Numbuh 1 is one of Numbuh 4's best friends, as stated in Operation: B.R.I.E.F.. And Numbuh 4 is like a little brother to him. When Numbuh 1 is leaving for the Galactic Kids Next Door in Operation: I.N.T.E.R.V.I.E.W.S., Numbuh 4 seems really angry and sad, most likely because he will miss him. When Sector V came to say good bye, Numbuh 4 was crying and was furious and told Numbuh 1 he and all of Sector V would come running to help him if ever needed it, showing just how much he cares about Numbuh 1. Later in the episode, a now adult Numbuh 3 states that 4 took it the hardest. In Operation: C.A.N.N.O.N. when Numbuh 1 came back, he saw a clam cannon and agreed with Numbuh 4’s idea since Numbuh 4 may have been pushy and bossy on Numbuh 2, 3, and 5 but the bright side was Nigel agreeing with Wally’s idea.
Numbuh 3
Numbuhs 1 and 3 are good friends throughout Codename: Kids Next Door. Despite the two being friends, Numbuh 1 is sometimes annoyed with Numbuh 3's antics and dizzyheadness as seen in Operation: K.A.S.T.L.E. and Operation I.-S.C.R.E.A.M., being opposites. However, Numbuh 1 cares for Numbuh 3 like a little sister as seen in Operation: H.O.M.E. when he tried to cheer her up after her My First Rainbow Monkey was broken. Kuki even cares for Nigel like a little brother and loves his leadership skills.
They have a brother-sister relationship as seen in episodes like Operation: F.A.S.T.-F.O.O.D., when Numbuh 1 let Numbuh 3 lead a mission for a day, though it was only to pick up burgers, knowing Numbuh 3 doesn't have what it takes to lead a real mission. However, he stated that Numbuh 3 was still part of the team and did not want to hurt her feelings.
It is hinted in Operation: W.H.I.T.E.H.O.U.S.E. that at one point he may have had a crush on her. Adult Numbuh 5 asks him "Who had a crush on Numbuh 3? And don't say Numbuh 4." to which he just gives her a knowing smile. This, however, was most likely a one-sided crush.
In Operation: I.N.T.E.R.V.I.E.W.S., as they say their goodbyes, Kuki gives him a kiss on his head and rubs it while Numbuh 1 looks at her with a smile and felt a little lovestruck and their brother-sister relationship would remain no matter what and how far they will be.
Numbuh 2
Numbuh 2 is another one of Numbuh 1's best friends, as said in Operation: Z.E.R.O.. The two are shown two be very close throughout the series and Numbuh 2 is like a big brother to Numbuh 1. In Operation: I.N.T.E.R.V.I.E.W.S., Numbuh 2 appears to be very sad when Numbuh 1 leaves for the Galactic KND, packing him "the essentials." And then shook hands. Numbuh 2 is really impressed by Numbuh 1's report in Operation: A.R.C.H.I.V.E.. And they were seen together in Operation: S.U.P.P.O.R.T. and Operation: H.U.G.S. And they are like brothers and Hogarth is like Nigel’s big brother.
Numbuh 86
Numbuh 1's relationship isn't always so friendly. Usually, 86 is seen yelling at Numbuh 1, as he is a boy, along with Numbuhs 2 and 4. In Operation: C.A.N.Y.O.N., she is impressed with Numbuh 1's idea to fill the Grand Canyon with Rainbow Munchies, until the Toiletnator flushed it all down. Still, in Operation: E.N.D it was revealed that Numbuh 1 and Numbuh 86 went to kindergarten together.
Vin Moosk
At first Numbuh 1 doesn't trust Vin Moosk, as he is an adult. Vin Moosk does, however, convinces Numbuh 1 to help him get rid of the ties after explaining he realized ties made him work a boring job. Numbuh 1 tried to help Moosk escape the queen tie when Windsor turned on them, and Moosk sacrifices not having to wear ties so Numbuh 1 didn't have to. Numbuh 1 is saddened by this, saying Moosk was their first cool adult he'd ever met. When Moosk is back at his boring accountant job, Numbuh 1 sends him some spray starch to get rid of the ties.
Enemies
Grandfather
Grandfather is one of Numbuh 1's most hated enemies, even though he is his real grandfather. When Grandfather has Senior Citi-zombified most people and the villains on the planet including Numbuh 2, 3, 4, and 5. Numbuh 1 teams up with his dad in order to restore the world, and succeeds in doing so. Something that really adds to the disliking factor is that Grandfather Senior Citi-zombified all of his friends.
Father
In Operation: G.R.O.W.-U.P., Father sent the DCFDTL to destroy the KND, and they turned Numbuh 1 into an adult. Numbuh 1 battles Father on many occasions, such as in Operations G.R.O.W.-U.P. and C.A.K.E.D.-F.I.V.E.. They had a short truce in Operation: M.U.N.C.H.I.E.S. because Knightbrace was going to destroy the last box of Rainbow Munchies, and, "Desperate times call for desperate measures." In Operation: Z.E.R.O, Numbah 1, his father and Father (who is revealed to be his uncle), band together once more to stop Grandfather.
Delightful Children From Down The Lane
The Delightful Children From Down The Lane are perhaps Numbuh 1's greatest enemies, despite being his cousins. For starters, they made him lose his hair, which he thought was really cool. Secondly, five times a year they have their birthday cake and try to keep it all to themselves. Thirdly, they are always trying to destroy the KND. For example in Operation: B.U.T.T., the Delightful Children blackmailed Numbuh 1 by using robot crabs to take pictures of his rear end but then they removed Nigel’s pants to show rainbow Monkey underwear as the Delightful Children laughed and laughed themselves silly and tried to have the robot crabs take a picture of Numbuh 1’s rainbow monkey underwear but Numbuh 2, 3, 4, and 5 came out of nowhere and removed the Delightful Children’s pants and skirts to make them blackmailed and Hogarth and Kuki made fun the Delightful Children’s “5 big butts”.
On only four occasions do Numbuh 1 and the Delightful Children get along. First was in Operation: Z.O.O. when they work together with his Sector to breakout of their cages in a Zoo, Second is Operation: I.T., when they gave him and Numbuh 362 the C.O.D.E.M.O.D.U.L.E. to track down Father to stop him The third was is in Operation: Z.E.R.O., where the DCFDTL are out of their delightful state to help Numbuh 1 defeat Grandfather. The last is in Operation: P.A.R.T.Y..
Chester
Chester imprisoned Numbuh 1 in a fantasy world in order to make money in Operation: U.T.O.P.I.A. and turned him into a moose in Operation: S.A.F.A.R.I.
Willard Wallace
Willard is perhaps one of Numbuh 1's greatest enemies, since Willard stole is father from him. In Operation: O.O.M.P.P.A.H., Numbuh 1 is willing to fight Willard by any means necessary to get his dad back, even play a sousaphone. Numbuh 1 plays the instrument for as long as he can.
Laura Limpin/The Big Badolescent
In Operation: C.A.K.E.D., Laura Limpin became the Big Badolescent when Numbuh 1, 2, 3, 4, and 5 and even the Delightful Children became worried about Laura whenever they changed their minds about the birthday things and cake as well and in Operation: Q.U.I.E.T., Laura came back again selling Skunky Scout Cookies and Numbuh 3 slammed the door on Laura’s face and she became the Big Badolescent and forced them to buy all the cookies and all the boxes until Stickybeard arrived to have them but had to eat them quietly since Numbuh 1 was sleeping.
Cuppa Joe
In Operation: U.N.D.E.R.C.O.V.E.R., Lenny (football helmet from the Delightful Children) was undercover and teamed up with Sector V to stop Cuppa Joe with coffee and stop the rest of the Delightful Children’s coffee supply but Lenny was sent as a spy sent by the other Delightful Children, who’s names are revealed to be Bruce, Alessandra, David, and Constance’s, scheme and the other Delightful Children had Lenny back but Lenny had put a bomb in a package, which they thought was the KND Secret Files and Cuppa Joe’s Coffee Rig exploded while Numbuh 2, 3, and 5 were thinking that the Delightful Children would act weird and crazy while drinking coffee like what happened to Numbuh 5.
Toiletnator
in Operation: Q.U.I.E.T., the Toiletnator came and was about to “flush” Numbuh 1, who was sleepwalking until Numbuh 5 used Professor XXXL’s snow cone to make the Toiletnator slip but made him land in a pillow. In Operation: F.L.U.S.H., the Toiletnator took out Mr. Boss, Mr. Timothy Fibb and Mr. John Wink, Crazy Old Cat Lady, and Knightbrace for Sector V, who was mad but they were at least glad and happy that the Toiletnator took out the villains for them. In Operation: M.U.N.C.H.I.E.S., Sector V accidentally ran over the Toiletnator’s back with Stickybeard’s ship. In Operation: C.A.N.Y.O.N., the Toiletnator got Numbuh 1, 2, 3, 4, and 5 in trouble when he flushed the whole cereal of Rainbow Munchies and Numbuh 86, the KND operatives and the villains chased after them and the Toiletnator.
Mr. Boss
Numbuh 1's greatest hatred for Mr. Boss was shown in Operation: D.A.D.D.Y. when Mr. Boss cut Numbuh 85's hair to an indescribable disaster and was going to do the same to Shaunie, Numbuh 1 was very angered, most likely because he'd lost his own hair already and found out that Mr. Boss was Numbuh 86’s dad. Numbuh 1 also declared Mr. Boss his sector's archenemy. But Mr. Boss agreed to let Numbuh 86 battle adult tyranny and Mr. Boss and the villains will make other kid’s lives miserable. Like most villians, Numbuh 1 has a general dislike for him.
Mr. Wink and Mr. Fibb
In No P in the Ool, Numbuh 1 used Mr. Timothy Fibb and Mr. Jonathan Wink’s chair to stop them but didn’t know how to work it and accidentally drilled a hole in the pool and the water drowned down and the kids, Sector V, and even Mr. Fibb and Mr. Wink got mad and they all had to use kiddie pool. And in Operation: C.O.W.G.I.R.L., Lasso Lass helped Numbuh 1, who had his doubts with Lasso Lass but befriended her anyway, and Numbuh 2, 3, 4, and 5 defeat Mr. Wink and Mr. Fibb, who ran away from being loved by Lasso Lass and Clip Clop and Mr. Wink and Mr. Fibb ran away as fast as their buffalo hooves and walrus flippers could carry them.
Crazy Old Cat Lady
In Operation: C.A.T.S., when Numbuh 4 accidentally destroyed Mr. Huggykins, Numbuh 3 forced him to dress up as her toy. He later got launched into the Crazy Old Cat Lady’s house where the Crazy Old Cat Lady mistook Wally, who was dressed as Mr. Huggykins, for a cat that talks. So Numbuh 1, 2, 3, and 5 came to rescue Numbuh 4. After Numbuh 3 saved Numbuh 4, he apologized and said, “I love you,” in Mr. Huggykins's voice, which resulted in a big hug by Numbuh 3. She later dressed up the Crazy Old Cat Lady as Mr. Huggykins, who was also forced to say “I love you,”.
Knightbrace
In Operation: T.E.E.T.H., Knightbrace got Numbuh 1 stuck in toothpaste and got him hooked on and used a paste to get Numbuh 1’s teeth shiny but the dentist Dr. Sigmund Teef, used taffy to stop Knightbrace. And in Operation: M.U.N.C.H.I.E.S. when Sector V was out of Rainbow Munchies, they went to the Supervillain Supermarket and Knightbrace stole it at the end to destroy them much to Sector V and the villains’ surprise at what Knightbrace was going to do to everyone’s favorite Rainbow Monkey Cereal so they and Sector V teamed up with the villains to defeat Knightbrace by giving him a tremendous beating and shook the Supervillain Supermarket and stuffed poor Knightbrace in the dairy fridge and his retainer was damaged and his eyes were spinning. He asked them to brush after every meal. In Operation: A.W.A.R.D.S., Numbuh 4 disguised himself as Knightbrace to save Numbuh 1, who was turned into an award by the villains. The other members of Sector V managed to grab him and run got him just in time before Numbuh 4 announced whether Father, Gramma Stuffum, Mr. Boss, or Stickybeard had won the award for Best Villain.
Count Spankulot
In Operation: S.P.A.N.K., when Count Spankulot teamed up with Sector V and defeated Mr. Timothy Fibb and Mr. Jonathan Wink, who were trying to take over playgrounds, by spanking them, the Kids Next Door tried to get rid of him by spanking the judge and his wife when he mistook them for Mr. Wink and Mr. Fibb and when Numbuh 3 gave everything away at what really happened, Count Spankulot got so mad, he gave the spankiest spanking on Sector V and in Operation: L.O.C.K.D.O.W.N., Count Spankulot hypnotized Numbuh 1 to go to jail where Count Spankulot took off his glove and spanked Numbuh 1 so hard, he got turned into a spank happy vampire like him and did the same to Numbuh 2, 3, and 4 and to Numbuh 3’s big bottom Rainbow Monkey, accept Numbuh 5, like Count Spankulot, who gave everything away and said that he used his powers to lure Numbuh 1 to jail and removed his glove and Count Spankulot turned Numbuh 1 into a spank happy vampire and did the same to Numbuh 2, 3, and 4 accept for Numbuh 5, who survived from being one too. The only way a victim can cure himself/herself of the Spank-Happy spell is to spank back the vampire that spanked him/her, or spank the original Spank-Happy Vampire. To which they broke the curse by spanking the spank-happy vampire and finally changing into their normal selves. And Count Spankulot was relieved that he was in jail and Numbuh 1 was out and was safe from being spanked but he was wrong. Sector V arrived at the jail with Count Spankulot and Numbuh 5 said, “You just broke the rules baby,” and then Numbuh 1, 2, 3, and 4, who were still spank happy vampires, said, “Looks like you…” “could use…” “a good…” “spanking.”,.
The Great Puttinski (Rupert Putkin)
In Operation: M.I.N.I.-G.O.L.F., Numbuh 1, 3, 4, and 5 got mad at Rupert Putkin (The Great Puttisnki) for laughing at Numbuh 2 for missing the golf hole.
Common Cold
In Operation: T.O.M.M.Y., the Common Cold kidnapped Numbuh 1, 3, 4, and 5 and even Tommy Gilligan as well and Numbuh 2 had his mother help out. In Operation: Q.U.I.E.T. when the Common Cold struck again, he was about to sneeze and wake up Numbuh 1 but Numbuh 2 stopped him but his hands got covered in boogers and snout. In Operation: S.N.O.W.I.N.G., the Common Cold got Numbuh 1 sick offscreen to go out in the snow.
Soccer Mom
In Operation: M.A.T.A.D.O.R., Soccer Mom used poor Numbuh 1 as the ball and poor Numbuh 2, 3, and 5 as the net until Numbuh 4 came to their rescue.
Mr. B.
In Operation: C.A.B.L.E.-T.V., Mr. B tricked Sector V by letting them have their own TV show and unleashed a robot called Homework-O, who grabbed poor Numbuh 1 and Mr. B used his cigar to activate satellites to use a baby ray to turn his victims into babies and Numbuh 1 used his glasses to bounce the ray away to the chain where Numbuh 2, 3, 4 and 5 were tied up and the chain got small and they were free and then Numbuh 1, 2, 3, 4, and 5 called Mr. B a baby considering he is one and spoke baby to Mr. B and lured him to the baby ray and he became an actual baby.
Mr. Fizz
In Operation: P.O.P., Mr. Fizz got Numbuh 1, 3, 4, and 5 in bottles until Numbuh 2 stopped Mr. Fizz by fiddling with the lever and got the soda in Mr. Fizz’s machine fizzled since shaking soda gets soda bubbly and when Numbuh 1, 3, 4, and 5 were free, Numbuh 2 forced Mr. Fizz to empty out all the bottles.
Professor Triple-Extra Large
In Operation: A.R.C.T.I.C. when Numbuh 1, 2, 3, and 5 attacked Professor Triple-Extra Large, he was creating “the perfect snow cone” and thought he was building a machine to stop all kids from having a snow day but he wasn’t. Professor Bob was. And in Operation: C.O.L.L.E.G.E. when Numbuh 1 snuck off to a college to look for a kid but it turns out Professor Triple-Extra Large was there and Numbuh 1 was the kid but didn’t mind because Professor Triple-Extra Large was making Numbuh 1 taste different snow cones until Numbuh 2, 3, 4, and 5 interfered.
Stickybeard
In Operation: P.I.R.A.T.E., Stickybeard first arrived at the Kids Next Door’s Treehouse and they got Numbuh 4, 2, 5, and 1 and then Numbuh 3 by catching her on the leg with licorice and then Numbuh 1, 2, 3, and 4 arrived to help Numbuh 5 in their treehouse pirate ship and then Numbuh 3 used gumballs to distract some of the Candy pirates, then Numbuh 1 and 4 used candy cane swords to sword fight more of the candy pirates, and Numbuh 2 fought the wheel of Gooey and Chewy. In Operation: Q.U.I.E.T., Stickybeard arrived and was about to wake up Numbuh 1 by breaking through the window but luckily Numbuh 2 opened the window just in time and was heading for some trophies but Numbuh 5 caught Stickybeard just in time too but Stickybeard arrived to battle Numbuh 5 since Operation: P.I.R.A.T.E. but stopped because he saw Skunky Scout Cookies and was having them but to eat quietly. In Operation: A.F.L.O.A.T., when Stickybeard saved Sector V from the Great White Asparagus, he stated that even though he doesn't like them, but he will never let a vegetable do anyone in, and made her promise not to tell anyone and she promises not to tell anyone. Numbuh 5 has a habit of calling him "Stickybun". And in Operation: M.U.N.C.H.I.E.S., Stickybeard showed up and blasted sugar sacks at Sector V and got the Rainbow Munchies twice but teamed up with Sector V and Count Spankulot, Mr. Boss, the Ice Cream Men, Crazy Old Cat Lady, Mr. Fizz, Mega Mom and Destructo Dad, and Father to attack Knightbrace, who stole the Rainbow Munchies to destroy them because of it does to someone’s teeth and gums and got beaten up but reminded them brush afterwards.
Gramma Stuffum
Unlike everyone else in the show, Numbuh 2 is the only one who enjoys Gramma Stuffum's cooking and is the Kids Next Door’s secret weapon to stop Gramma Stuffum, although he himself said her food was 'disgusting', saying cheesy phrases like, "It's snack time, Fraulein!" or, "I'm sending this dish back to the kitchen", much to Numbuh 5's chagrin. For example in Operation: N.O.-P.O.W.U.H., Gramma Stuffum arrived and fattened poor Numbuh 1, 3, 4, and 5 up but Numbuh 2 came to save the day with his “big appetite” but was stuffed up until the hamsters came back to help and used the rubber band food flinger to get rid of her and Liver and Onions and in Operation: F.O.O.D.F.I.T.E., when Sector V came to school to have lunch, Gramma Stuffum arrived again and sung a song about kids eating and Numbuh 2 was still the secret weapon to stop her.
Mega Mom & Destructo Dad
In Operation: C.H.A.D. when Numbuh 1, 2, 3, 4, and 5 went to help Chad, Mega Mom and Destructo Dad arrived and stupefied them until Chad, who was none other than Mega Mom and Destructo Dad’s son, stopped them by quitting things.
Ice Cream Men (Normal/Elite)
In Operation: I.-S.C.R.E.A.M., Numbuh 3 was begging the Ice Cream Men’s ice cream machine for ice cream but didn’t know the password and Numbuh 1 forced the Ice Cream Man to tell the password, which was Frosty. And when the Ice Cream Men and the Delightful Children unleashed an Ice Cream Monster at the Ice Cream Factory. The Ice Cream Monster got Numbuh 1 stuck on the wall with cones, Numbuh 2 smashed with ice cream, Numbuh 4 stuck in chocolate, and Numbuh 5 covered in vanilla ice cream with a cherry on top until Numbuh 3 defeated it with a heater and caused an ice cream flood as she, and Numbuh 1, 2, 4, and 5 and 2 children sung, “Party. Ice Cream Party,” into the sunset. In Operation: L.E.A.D.E.R., the Ice Cream Men attacked Sector V at the Ice Cream Shop and when they were defeated, Numbuh 2, 4, and 5 laughed at Numbuh 1, who was covered in ice cream accept for Numbuh 3, who wanted ice cream. In Operation: P.R.E.S.I.D.E.N.T., the Ice Cream Men struck again to kidnap Jimmy Nixon McGarfield, who was a robot. In Operation: C.A.K.E.D.-F.I.V.E., Numbuh 1, 2, 3, and 5 went to save Numbuhs 86 and 19th Century while Numbuh 4 stayed on Earth in a wooden cake to surprise the Delightful Children.
The Proper Patrol (Major Manners and Sergeant Sensible)
In Operation: C.A.N.N.O.N., while Numbuh 1 was away, Numbuh 2, 3, 4, and 5 were relaxing when the Proper Patrol (Major Manners and Sergeant Sensible) arrived and blasted Numbuh 2, 4, 5, and 3 to make them wear “proper” clothing after Count Spankulot spanked Numbuh 2, 3, 4, and 5 at first and blasted off.
Mrs. Goodwall
In Operation: Z.O.O., Numbuh 1 encountered Mrs. Goodwall, who told Numbuh 1 about the Children’s Zoo where Numbuh 1 didn’t want to pet a goat, and captured Sector V and some nerd, gossip, and ugly children including the Delightful Children From Down the Lane, who teamed up with Sector V to escape, and took them to a “children’s zoo”. And when Numbuh 1 and 5 pretended to say, “sorry,” to Mrs. Goodwall, they made her back up where she got stampeded by Numbuh 2, 3, 4, and the nerd, gossip, and ugly children. Later Numbuh 5 wached Mrs. Goodwall getting chased by the Schoolyard Bully.
Big Brother
In Operation: M.I.N.I.-G.O.L.F., Numbuh 1, 3, 4, and 5 were being chased by Big Brother but Numbuh 2 arrived coming on his D.A.R.T. and missed at first but knocked Big Brother out after bouncing around some objects.
Parent Teacher Organization Of Eradicating Youngsters
In Operation: N.O.-P.O.W.U.H., the Parent Teacher Organization of Eradicating Younsters attacked the Treehouse and some magnifying glass lasers got the Principal, Numbuh 4 got Mad Dad, Numbuh 3 got the Terrible Tutor, Numbuh 2 and Numbuh 5 got the Heli-Teacher, and Numbuh 1 got Midwestern Mom.
Interesting Twins From Beneath The Mountain
In Operation: T.R.I.P., the Interesting Twins From Beneath the Mountain arrived and followed Numbuh 3 all day long to the top of a mountain and in Operation: R.E.C.R.U.I.T., when the ITFBM returned again, they were in a boy named Bobby, and somehow Numbuh 1, 2, 3, 4, and 5 knew it was them and made the Interesting Twins go on a wild-goose chase to get attacked by Mr. Wink and Mr. Fibb and the Crazy Old Cat Lady.
Rivals
Chad (Numbuh 274)
Numbuh 1 was close with Chad when he was a cadet, choosing Chad to be his mentor. Numbuh 1 admired Chad until Chad betrayed the KND. At the end of Operation: T.R.E.A.T.Y. when they were dueling, Numbuh 1 kept scolding Chad. When Chad was revealed to be a TND agent, Numbuh 1 stood down. After Numbuh Infinity's and Chad's departure, Numbuh 1 was pretty sad. Both of them are two of the greatest KND operatives ever.
James Nixon McGarfield
Numbuh 1 and Jimmy are shown to be on good terms in Operation: P.R.E.S.I.D.E.N.T., with Numbuh 1 being encouraging and supportive of the then-4th Grade President. But by Operation: S.N.O.W.I.N.G. they have become enemies, especially since Jimmy kidnapped Numbuh 1's girlfriend Lizzie and tried using a modified boyfriend helmet to make her his girlfriend against her will.