These are the relationships Darwin has with the other characters in the series.
FamilyThe Origins," showcasing that the two brothers had special connection from the beginning.
As evidenced by "The Sidekick," Gumball looks up to Darwin as a moral guardian, with Darwin being the morale to Gumball's craziness. It is because of this that Darwin can get awfully critical of Gumball when he believes that he has crossed moral line. Despite this criticism, it is all done as an act of love.
Like he is towards his other family members, Darwin is very affectionate towards Gumball and can be especially overprotective of him, as seen in "The Safety" when he became overly paranoid.
Darwin can be somewhat clingy towards Gumball and does not like being left out most likely deriving from the fact that up until recently, Darwin has always been near Gumball and has not made many independent choices of his own. The fact that Gumball was almost directly responsible for his evolution into his current form is likely another reason. When Gumball starts dating Penny after the events of "The Shell," Darwin goes through a brief but intense phase of jealousy directed at Penny; he fears being left alone without his older brother to care for him.
Though Darwin is not as attached to Anais as he is to Gumball, the pair share a rather close sibling relationship. The two share an interesting dynamic in that Darwin is a romanticist, while Anais is a realist. In "The Curse," while Anais tries to prove to Gumball that his bad luck is mere coincidence, Darwin tries to form a formal (though romanticized) hypothesis to appease Anais' formal argument.
The two have a strong trust bond, as shown in "The Plan" where Anais responds "of course" when Darwin asks if he trusts her to throw her safely over a wall, although this particular case shows Anais trusting him was a bad decision. In "Halloween" Anais was seen holding Darwin's hand when he was scared whilst walking through the graveyard suggesting that Darwin may see Anais as a sort of "older sibling" figure despite her age.
Both siblings can often play as "straight men" to Gumball's more bizarre decisions. In "The Plan," the two teamed up to tell Gumball that he was approaching the e-mail portion of their plan wrong and in "The Oracle," both attempted to make Gumball's attempts to avoid his fate more feasible. In "The Roots," Anais tells Darwin he is her favorite.
Though the two do not seem to interact very often, Nicole sees Darwin as her own son and is rather affectionate with him, in turn he sees her as his mother. When she speaks to Gumball or Anais, she refers to Darwin as "your brother." Due to Nicole's general stressful character, the fact that Darwin's outlook is to appease everyone, he is rarely the center of her wrath. In "The Mothers," when Gumball offers to rework a sign to impress Nicole, Darwin strongly suggests just following her orders and sitting in the car, implying that he respects her parental authority.
Darwin expressed his affection for Nicole in "The Mothers" as he was determined to prove to his friends that Nicole was indeed the best mom and was very excited to tell his mom when she eventually ended up winning the competition. In "The World," Darwin and Nicole are shown to be grocery shopping alone, suggesting that they do spend time together occasionally.
In "The Meddler," although he admitted that he was embarrassed about having his mother around him and Gumball in school, he forced a smile on himself so he would not hurt Nicole's feelings, once again showing the closeness between the two as Darwin hates hurting loved ones.
As expected from Nicole, she too is also very affectionate of Darwin. In "The Roots," she is distressed when evidence initially led her to believe that Darwin was unhappy with the family; she did everything in her power to make sure that Darwin was happy with the family. She was also deeply saddened by Darwin's temporary absence in the episode.
Despite this, Richard can still exercise his authority towards Darwin when necessary, such as in the events of "The Password," where the Watterson brothers constantly harassed Richard in order to win the title of "favorite child" (even though it was all an elaborate ploy by their sister).
Darwin may also desire to see Richard grow as a father figure as episodes such as "The Castle" have Darwin encouraging Richard to take more parental authority.
Like Nicole, Richard is very affectionate of Darwin and would do anything in his power to ensure his safety (even though his incompetence may prevent him from doing such in the most efficient way). When the family thought that Darwin was going to leave in "The Roots," he too lost it and became uncharacteristically depressed and distressed.
During "The Goons," Richard stated that Darwin was his favorite child (though he denied that it was the case upon seeing the expressions of Nicole and his other children).
Darwin does not really interact much with his grandmother, but in "The Kiss," he says that he likes being kissed on the cheek (by her, although he does not say specifically) because it makes him feel special. In "The Authority," Granny Jojo keeps him and the rest of the family (except for Nicole) in the house to keep them safe showing that Darwin and the rest of her grandchildren hold a very special place in her heart. In "The Man," Darwin (with Gumball and Anais) helps Granny Jojo meet up with Louie in order to ensure her happiness.
Even though Darwin loves Granny Jojo, "The Check" shows that he is very off put by her traditions that come with her old age.
Even though Louie is a fairly recent addition to the Watterson family, he still expresses a decent amount of care towards Darwin and his siblings; likewise, Darwin does the same.
In "The Man," Darwin was very supportive of Louie's relationship with Granny Jojo, wanting both parties to be happy; Darwin went against his father's orders in order to allow the two's relationship to continue.
When he is later married to Granny Jojo and becomes the Watterson children's step-grandfather, Louie gives a gift of $50 (that the children initially believed to be $5000) as gift for "being his favorite grandchildren."
In "The Catfish," both Watterson brothers feel sorry that grandpa Louie does not have any friends sans his wife, so they create a false Elmore Plus account pretending to be a woman interested in befriending him. In spite of the destructive consequences, they do prove that they truly care about their grandfather.
Carrie and Darwin have been friends since the start of the series. However, it would appear that some time before the events of "Halloween," Carrie also becomes Darwin's love interest, as when he becomes a ghost, the first thing he does is kissing her on the lips, claiming it's been something he's wanted to do for a long time, to which she reacts with a blush.
Although not much is shown about their feelings for each other during other episodes, in "The Scam" those are much more heavily implied. Carrie even appears to reciprocate Darwin's feelings. Gumball uses the thought of getting closer to Carrie in order to tempt Darwin into following through with their scam, causing him to have a brief romantic fantasy about her. Then, when Carrie required a body to possess in order to eat the candy they gathered, she sheepishly asked Darwin to borrow his, causing him to get nervous as well. Later, Darwin expressed great sadness when Carrie was about to get married to Gargaroth and whisked away to the underworld forever. At the end of the episode, they each awkwardly tried to find an excuse to get the other to hang out with them.
In "The Matchmaker," Darwin shows more passion for Carrie than ever and is even more anxious to impress her, going as far as writing a poem, a song and shout out his secrets in her presence. However, due to Gumball's misunderstanding, Carrie reluctantly makes a love potion to use on Darwin and Teri, making them fall in love. After realizing the mistake, Gumball and Carrie try to break them up, only to bring them closer in the process. But when Darwin notices Carrie's heartbroken tear, the spell breaks and he approaches the former and the two finally build up the courage to kiss.
It is confirmed in later episodes that, as of the end of "The Matchmaker," they are officially dating.
Darwin and Penny share a friendly, yet platonic relationship. As seen in episodes such as "The Storm" and "The Flower," Darwin and Penny hang out in a very friendly manner, often making small talk and goofing off.
Darwin is generally very supportive of Gumball's relationship with Penny. However, after Gumball and Penny began dating ("The Shell"), Darwin became jealous about how much more time his best friend is spending with his girlfriend. Although he does want Gumball and Penny to be happy, he could not help but feel threatened by their relationship, fearing that he would be alone. This is first hinted at in "The Burden," and later explored in "The Bros," in the latter of which Darwin repeatedly attempts to either sabotage their relationship, or alienate Penny completely. This causes Penny to briefly break up with Gumball, but Darwin regrets his actions and helps get them back together later. Nonetheless, it is still hinted that he seems to generally be at odds with being the third wheel. However, it seems that Darwin has gotten over these feelings, as he did not show any hostility when he assumed Gumball was inviting Penny over in "The Traitor" and he helped the former setting up a romantic quest for Penny in "The Romantic." The two also appear to have re-established their friendship as evidenced in "The Ex," where they are shown hanging out together while talking about nemeses. Penny is also amused when Darwin mentioned his own nemesis.
For the most part, Darwin and Banana Joe seem to share a very good friendship; however, in earlier episodes, Banana Joe does not seem to be as friendly with Darwin as he is in later seasons. In "The Gi," he maliciously made fun of Darwin's karate outfit, without any remorse whatsoever.
In "The Banana," Gumball accuses Banana Joe of chewing Darwin's pen, but Darwin did not seem to mind. Later, though, when he sees Joe trashed his desk and homework, he goes through a rampage through Joe's stuff in hatred and revenge. Later, still, when Joe offers him a new pen, Darwin feels remorse for what he has done. When Joe reaches his locker, he attacks Gumball and Darwin, but accidentally knocks himself out. Finally, Gumball and Darwin beat themselves up in an effort to make up with Joe, which succeeds, and they become good friends again at the end of the episode.
In "The Promise," it is revealed that Darwin cares a lot about his relationship with Banana Joe - when Joe gets mad at him, he does everything in his power to restore their friendship, to the point of breaking his promise with Gumball to play The Tale of Zelmore.
From this point forward, Darwin and Banana Joe seem to be very cool with each other, often hanging out and going for ice creams, as seen in "The Roots." Banana Joe also plays harmless, friendly pranks on Darwin, such as the one he pulled in "The Butterfly."
Darwin and Bobert appear to be quite friendly towards one another despite their initial rocky start. In "The Bet," Gumball and Darwin feel sorry for Bobert having no one to play with, so allow him to play with them; however, when one of their games involve Bobert entering slave mode, Darwin calls Gumball out, believing that Bobert needs to be treated with care due to his circumstances.
In "The Upgrade," Gumball and Darwin convinced him to upgrade into a new version. During the same episode, Darwin along with his brother come to the realization that they much prefer the original Bobert as they have come to know the original Bobert as their friend, and not a product.
In "The Love," both him and Gumball were shocked to discover that Bobert did not understand the concept of love, and the two were eager to teach their friend the joys of love.
Although they differ in age quite a bit, Rocky is a decent friend to both Gumball and Darwin. In "The Boss," both Darwin and Gumball help Rocky out by finding him a traditional office job so that he may once again connect with his dying father.
As seen in "The Slide," Darwin, Gumball, and Rocky are all gaming buddies, often playing an online MMORPG together; in that same episode, Darwin, along with his brother, help Rocky find love in his life.
Although Ocho's relationship with Gumball is complicated, Darwin himself is on decent terms with Ocho. In "The Phone", Ocho is one of the first kids Darwin gives his new phone number to, and from there, Darwin is addicted to texting and calling Ocho. Later in the episode, Ocho's temper leads to a brief conflict between the two, but it is quickly resolved.
Mr. Robinson is somewhat an idol to both Darwin and Gumball. With his brother, he always tries to earn his favor as shown in "The Poltergeist," "The Car," and "The Boss." Ironically, Mr. Robinson despises both Gumball and Darwin for irritating him all the time. In "The Sale," Darwin, along with Gumball, worked to prevent Mr. Robinson selling his house.
Darwin has no romantic feelings for Masami, as seen in "The Pressure." Although Masami lies that Darwin and her are dating just to impress the other girls, this forces Darwin to go with her to the tree-house. When they were about to kiss, Banana Joe cuts down the tree, and Darwin slides away and ends up kissing Gumball, who was about to kiss Penny.
Later in the series, it is shown that Masami and Darwin are on decent terms. Darwin, along with Gumball both try to get Masami the best birthday possible in "The Gift" (though this act was more likely done out of fear rather than friendship), and they talk casually in "The Fury."
Sarah has a huge crush on Darwin (and Gumball) and cannot help but stalk him. But unlike Gumball, Darwin is much more patient with Sarah, such as in "The Fan," when Gumball and Darwin hurt her feelings and sent her away, Darwin immediately regretted his actions and wanted to make it up to her.
In "The Comic," Darwin speaks to Sarah as if she were a friend; he expresses his disdain for comic book heroes, only to dress up as a LaserHeart's sidekick, Smooch when Sarah mentions Darwin's inclusion in her fan-comic.
In "The Test," the two seem to be very casual towards each other, often exchanging jokes and tomfoolery with each other.
In "The Potato," Sarah, along with Gumball, is more than happy to help Darwin stop his obsession with potatoes. She is also worried for him when Idaho comes to his house while he is trying to overcome the obsession.
Tobias and Darwin's relationship has never been too prominent. In "The Third," Tobias became Darwin and Gumball's friend (for the price of $20). The two quickly became close friends, due to Tobias being athletic and rich, leaving Gumball out. By the end of the day, Darwin and Gumball had reunited, from then, Darwin, along with Gumball refused Tobias to join in with them any further.
It is shown in "The Words" that Darwin finds Tobias annoying because he constantly gestures something known as "chunking the deuce." When Darwin finds out Tobias and his mother cheated in the mom-off event in "The Mothers," he is further disappointed in the rainbow lad.
Darwin finds even more annoyance with Tobias in "The Slap," finding his new greeting to be very invasive and demeaning.
Darwin did not interact with Mrs. Robinson much until "The Wicked." At the beginning of the episode, Darwin had no ill feelings toward Mrs. Robinson's evil intentions, and continuously ignores Gumball's comments about her, because he had the belief that there is no such evil exists. However, his belief has changed once she ignored helping him while he is choking, and closed the door on him. After this, Darwin is filled with true vengeance and rage, and he only desires to get back at her.
Rob was initially friendly with Darwin and his brother before he was sent to the Void. Once he escapes and regains his memory, however, Rob swears vengeance on Gumball and Darwin, promising to destroy everyone they have ever loved. This hatred is mostly one-sided, as for the most part, Darwin has no ill-will towards Rob. Rob's hatred for Darwin also seems to die down a bit (though not by much) when he starts focusing all his energy towards Gumball.
Although Darwin and Jamie never interacted much prior to the events of "The Girlfriend," Jamie still chose him to be her boyfriend; in the short time span that their relationship existed, Jamie proved to physically and verbally abusive when interacting with Darwin. When their relationship came to a close, Jamie gave Darwin a nice sucker punch to his face because he "treated her like an idiot."