This article focuses on the relationships between Numbuh 5 future supreme leader of the KND and members of the show.
"Aw...Why don't ya get yourself a boyfriend?!" - Numbuh 5 in Operation: K.I.S.S..
Cree Lincoln is Numbuh 5's older sister. The two sisters were once close, but now have a bitter rivalry when Cree betrayed the KND. In Operation: K.I.S.S., it's revealed that Cree knows most of Numbuh 5's fighting skills and styles because she taught most of them to her. As well, it reveals that they were once really close sisters as shown in Operation: M.A.U.R.I.C.E. where Cree gives Abby her hat for being proud of her.
In the same episode, Cree wishes that Abby would join her on the Teen Ninjas side instead of fighting her on opposing sides. They also put on shows in front of their parents to give the illusion that they do not fight each other, which does work out. In Operation: V.I.R.U.S., it's shown that Numbuh 5 and Cree still care about each other as sisters, even if they are technically enemies.
- "DAAAD!" - Numbuh 5 in Operation: S.U.P.P.O.R.T.
Mr. Lincoln is Numbuh 5's dad. He's shown some speaking roles in Operation: S.U.P.P.O.R.T. and such. It seems that Numbuh 5 gets most of her father's traits such as similar speech patterns: "You know the clowns with their cartoon and puppets and the stuff and-etc." It could be inferred she is physically similar to her dad as she has the same skin tone as him though we haven't seen his face. In Operation: C.L.O.W.N., Abby seems very close to her father. Like Cree they both get annoyed when their father embarrasses them.
- "Moma..." - Numbuh 5 in Operation: C.H.O.C.O.L.A.T.E..
Mrs. Lincoln is Numbuh 5's mother. She's only seen in a few episodes, but not much is known about their relationship besides that she is her mother.
- "Whoa... she's beautiful..."
- "Yeah, yeah. Now grab your girlfriend and let's go save the others." - Numbuhs 2 and 5 in Operation: U.N.C.O.O.L.
- Numbuh 2 [Hoagie Gilligan] was introduced as one of Numbuh 5's closest friends. Their relationship is seen through most of the horrible puns that Numbuh 2 makes like in Operation: R.A.B.B.I.T. and Operation: C.L.O.W.N.. In Operation: U.N.C.O.O.L., Abby shows much annoyance when Numbuh 2 would go on about saving Numbuh 78 and how important it was to him (though she becomes enraged when she learns it's just a Yipper trading card). Similarly, in Operation: C.O.U.C.H., she quickly elbows Numbuh 2 for mentioning Numbuh 10 is "easy on the eyes". In Operation: B.E.A.C.H., they are together for the most part throughout the episode and even held hands to make fun of Numbuh 4's feelings that he will never get. In Operation: F.O.U.N.T.A.I.N., they briefly put their arms around each other.
In Operation: D.A.T.E., she decides to go with Numbuh 2 after Numbuh 1 suggests to pair up so as to not put up suspicions. Also, in "The Grim Adventures of the KND", she seemed to be the most alarmed when the Delightful Reaper assimilated him. In Operation: Z.E.R.O. , they are shown holding hands while sliding down the ship's wreckage. Later in the series, Numbuh 2 begins directing his jokes towards Numbuh 5 more than any other member, in the hopes of making her laugh. In Operation: K.I.S.S., Cree gives a statement saying: "And he's [Hank's or Numbuh 2's] cuter than anyone you'll ever date,". However, towards the end of the series to the last episode, Operation: I.N.T.E.R.V.I.E.W.S., it's revealed that Numbuh 5 is married to Numbuh 2.
- "So what? He's just talkin' to a super cute...Oh, heh...Wait a minute...You're not JEALOUS, are ya?"
- "Are you CRAZY?!"
- "Don't worry...It's just a stupid BABY CRUSH!" - Numbuh 4, Numbuh 5, and Cree in Operation: M.A.U.R.I.C.E.
Maurice (current Teens operative for the KND) was introduced in Operation: M.A.U.R.I.C.E. and throughout the episode, there are many of hints showing Numbuh 5's interest in Maurice. She admired him three years ago when they were in the same Sector.
Then those three years later, she goes out of her way to try and save him from the Teen Ninjas and to try and prevent him from getting recruited. Towards the destruction of Chicken Pox Island, Maurice holds her hands and looks in her eyes reassuringly to trust him and she does. Towards the end, she winks at him after he winks at her, knowing that he's still a part of the Kids Next Door. Despite this she apparently realized this was an infatuation as she eventually married Numbuh 2.
- "We told him everything that he wanted to know...Oh! And Numbuh 1...Welcome back." - Numbuh 5 in Operation: I.N.T.E.R.V.I.E.W.S..
Numbuh 5 is the closest to Numbuh 1, cheering him up when he is down as seen in Operation: I.N.T.E.R.V.I.E.W.S.. Numbuh 1 thinks highly of Numbuh 5, placing her as his second-in-command, even comments that she has more common sense than him, which is shown in many episodes. Occasionally, they are at odds with each other (as seen in Operation: D.I.A.P.E.R.) due to the fact they tend to share different beliefs. They are, regardless, great friends and continued to be close throughout the series.
Numbuh 5 always turns down every offer to be leader of anything, which is shown multiple times throughout the series such as Operation: F.E.R.A.L. and Operation: I.N.T.E.R.V.I.E.W.S. It is later revealed in Operation: F.O.U.N.T.A.I.N. her refusals to be leader link back to an event early in her KND career. Though the event is never fully explained, it is known that it involved the Delightful Children somehow capturing Numbuh 1. Numbuh 5, being leader of Sector V at the time, had decided against helping him, which resulted in his permanent baldness. She fears being leader again and making the same mistake.
- "Chill Numbuh 3, we are not going anywhere, we just need a plan." - Numbuh 5 in Operation: H.O.M.E..
Numbuh 5 sees Numbuh 3 as a best friend and a sister figure to her as they are the only 2 female members in Sector V. Despite being opposites, Numbuh 5 usually helps Numbuh 3 with problems and comforts her when she is feeling hurt and down as seen in Operation: H.O.M.E.. They can usually relate to each other as they seem to think alike. It is shown that they both like Rainbow Monkeys and reading magazines. She also aware of Numbuh 4's crush on Numbuh 3, but tends to tease Numbuh 4 about it more than she does Numbuh 3. However, the 2 female members are indeed different as Numbuh 5 is the oldest member, whereas Numbuh 3 is the youngest.
"We're the Kids Next Door, Numbuh 4. That's our job!" Numbuh 5 in Operation: F.O.U.N.T.A.I.N..Numbuh 4 and 5 have a brother-sister relationship, both having similar personalities and are the best fighters on their team. Because of that, the two are often paired up when it comes to fighting enemies and on missions. However, Numbuh 5 loses her patience with Numbuh 4 on many occasions as seen in Operation: L.O.C.K.D.O.W.N. and she would often argue and disagree with him over his KND duties as seen in Operation: F.O.U.N.T.A.I.N. and would hit him with her hat.
Nevertheless, they remain very close, their relationship was the main focus in Operation: D.O.G.H.O.U.S.E., Numbuh 5 being shown to help him with his homework. In the same episode, it was also shown due to his determination and bravery, Numbuh 4 will usually be the first person Numbuh 5 comes to for an overwhelming situation.
Numbuh 5 repeatedly teases Numbuh 4 about his crush on Numbuh 3, much to the chagrin of Numbuh 4, but there are times when Numbuh 4 teases her back. In Operation: M.A.T.A.D.O.R., Numbuh 5 would calls Numbuh 4 by nicknames such as "sport" and and would give him a noogie.
She would sarcastically call him "genius" and "Einstein" (due his low intelligence). Overall, they both look up to each other and depend on each other at times and remain close friends.
"Because you're more important to me than candy." -Numbuh 5 in Operation: C.A.R.A.M.E.L..
Henrietta and Numbuh 5 have a history as rival candy hunters, both being friends 5 years ago before the show started. When they were young, Abby and Henrietta were in Guatemala, trying a magic ritual. The ritual that they performed that took away the most valued quality of the human in question and turned their quality into five pieces of delicious caramel with flavor depending on the quality taken.
When Henrietta did this to herself, she selfishly ate nearly all of her caramels, causing her to lose her femininity, the quality she sacrificed, forever. Knowing that Henrietta could not control her greed, Abigail left her behind, and Henrietta blamed her for bringing this curse upon her. What she didn't know was that Abby took the last caramel for safekeeping, and kept it for five years until the time when the curse could be reversed.
Their relationship has been strained since the "Guatemala Incident", but Numbuh 5 tries many times to reach out to her old friend and stop her from her candy schemes. Henrietta rejects this, since she is determined to get revenge for Abby's apparent betrayal.
Number Five has helped Henrietta on a few occasions, despite being her rival. In Operation: C.H.O.C.O.L.A.T.E., she brought her back to the Kids Next Door Arctic Base after defeating her in battle, where KND scientists managed to turn her back to a human from her chocolate monster form. In that same episode, she brought Henrietta a cheeseburger while she was in prison, which she was grateful for since she'd only been able to eat chocolate for months. She also saved Henrietta's life in Operation: L.I.C.O.R.I.C.E. when she was kidnapped by Black John Licorice and his crew. When Abby noticed Henrietta was missing from the Arctic Prison, she went to Stickybeard and was able to get his help in finding her. There, Abby was able to distract Black John and his crew long enough to save her friend. Henrietta thanked her afterwards for saving her life, but when asked if it made up for Guatemala, she responded angrily by saying what happened in Guatemala was unforgivable.
In Operation: C.A.R.A.M.E.L., after much trouble, Henrietta finally learned how to share her candy with Numbuh 5, and thus returned to her regular form, a beautiful girl. Afterwards, Henrietta thanks Abigail for never giving up on her and they make amends, leaving Henrietta to fix the wrongs she had done.
Similar to her relation with Henrietta, Numbuh 5 and Stickybeard have a fierce, but respectful rivalry. Numbuh 5 usually outwits Stickybeard during their battles, as each of them try to be the best candy hunter. 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. Numbuh 5 has a habit of calling him "Stickybun".
Numbuh 5's hatred of Father is the same as the rest of Sector V's, due to his evil nature and cruelty to kids.
She seemed to hate Mandy in The Grim Adventures of the KND when she takes over as Supreme Leader over Numbuh 362, and they have a deep argument continuously, arguing about telling the others that she is not Numbuh 1 and she's only pretending. This causes the others to believe that she is Numbuh 1, including Numbuh 362. Later, when Numbuh 1 and Grim arrive at the Moonbase, Numbuh 1 discovers this, but is stopped by Numbuh 60, who backs her up. since he still didnt know she was lying She's a really sick person
As is her hatred for Father, her hatred for the Delightful Children is the same as the rest of Sector V's. If anything, her hatred might even be more than her hatred for Father, for it was their fault that Numbuh 1 lost his hair and is permanently bald.