Crackerdile/Relationships

Brash
Crackerdile's relationship with Brash is complicated as well as important, the two of them used to be partners when working at S.U.I.T, and they got along very well, becoming close to the point that Crackerdile came to refer to Brash as a friend, That's how it was until the incident on their last mission together. Crackerdile began to despise Brash for not checking up on him after what had happened, and when he noticed Brash had gotten a new partner, he assumed that he's already moved on and became jealous, and being a toxic radioactive cracker, this intensified his emotions more and made him decide to a villain, to wreck havoc and get his revenge on Brash.
Crackerdile does not reconsider his way of seeing Brash, although Brash himself more than once tried to clarify the situation and show him that he was wrong, he continues to insist on his belief that Brash was to blame for his death and everything else, and tries to continue taking revenge against him, carrying out many impulsive actions to achieve it, actions that constantly put the own Crackerdile at risk of getting hurt too. In InvestiGators: Off the Hook Daryl, turned into a giant Waffledile, swallows Brash in one of his attempts to take revenge against him by suffocating him, causing Brash to go into a coma.
In InvestiGators: Braver and Boulder, Daryl finally manages to have a calmer conversation with Brash, in which he clarifies how he felt after his "death", and accepts that his way of seeing Brash was the wrong one and everything that happened wasn't Brash's fault, becoming on good terms with each other again and leaving every bad action behind, this for Daryl to just to say goodbye to Brash before he died again.

Mango
By having interactions that do not occur voluntarily, the relationship between Mango and Crackerdile is somewhat distant, as it is based more on the union that both have with Brash, starting when Crackerdile saw that Brash had "replaced" him with Mango as his new partner.
Crackerdile always tries to confront or confuse Mango so he gets out of his way, and thus makes it easier for him to take revenge against Brash, sometimes he does this by threatening Mango with harm or attempt against the life of Brash, or when Brash mind's version of him used to blame Mango for his partner being in a coma.
Therefore, he is usually annoyed of the presence of Mango, and rather than being a personal dislike, it is because Mango intervenes in his objective, and is agent of the enemy side, S.U.I.T Headquarters. By the rest, have not had such a deep relationship or many interactions so far out of confrontation.

Prime Robot
On InvestiGators: Take the Plunge, upon discovering the existence of Prime Robot, Crackerdile suggests that they should team up in order to him being able to obtain a V.E.S.T. More than it being a genuine relationship, Crackerdile saw Prime Robot as a way to obtain his goal, getting angry with it when it did not give him his V.E.S.T, and giving it a "hug", merging his body with Prime Robot's and getting the V.E.S.T, but turning into dough after that.
Due to this book being the first and last one where Prime Robot appears, Crackerdile has not been related to it since, with this interaction being simply just another attempt of him to manipulate someone to get what he wants.

Hookline and Slinker
Crackerdile teams up with Hookline and Slinker, and help them to become part of the T.A.I.L Blazers, Crackerdile orders them to help him find a new physical form, as well as looking for a place where they can have a secret lair for T.A.I.L Blazers. Similar to what happens with Prime Robot, Crackerdile relates to them more than anything to seek help and some alliance, in order to take advantage of their work, and when Hookline and Slinker manage to turn Crackerdile into *Waffledile*, they decide to attack Dr. Doodledoo to turn Waffledile into a giant.
Close to the end of the book, Bill Plungerman comes back to normal and stops being Hookline and Slinker, helping Mango to get Brash out of Waffledile's stomach.