Disclaimer: I do not own Descendants.
The dynamics of the Isle were set at an uneasy plateau- territory boundaries had been hashed out before he had been born, but that would only hold for as long as the original adherents could hold them. The initial occupants weren't getting any younger and the children of the Isle were getting older (and less inclined to hold to the limitations just because they were told to do so by the day).
It was not the place for a boy who didn't want intimidation to always be the first course of action to try to fumble his way into adulthood. He kind of hated everything about being an alpha. There were expectations that came with such a situation that made things decidedly uncomfortable on the Isle. His mother was as pleased as she ever was about anything, but that hardly made up for the fact that this was the Isle of the Lost. Betas were destined to be minions. Omegas were destined to be slaves. Alphas were destined to spend their days fighting over what illusions of control and territory might be carved out in the wasteland that was their home.
His best bet was to find some corner of the Isle where he could unobtrusively carve out a small life for himself that didn't encroach on any of the others and hope that they forgot about him in the midst of more vocal considerations. It was just too bad that he had people around him that were so determined to push him forward on a path he didn't want to travel.
He did not want people to fear him. He wanted to be followed because he was a good leader with sense and dedication - not because they were afraid that he might beat them or have them executed if they crossed him.
Sadly, the Isle was not the place for the sort of alpha that he seemed to be. The Isle was all he knew, but he still knew enough to know how twisted everything was. Alphas who misused their gifts were the order of the day. It was a wonder that more than half the children on the Isle did not have Gaston as their father the way such power was wielded. Actually, he was not quite certain that that was not the case in truth. The type of alpha the Isle approved of had led to a lot of bloodshed in those early days. While there was no official census of the Isle, he was relatively certain that the population had been halved in the course of the first two years - it only left so many parental options. Everyone knew that Gaston only kept on his paramours that produced boys. It was an open secret that if you were a girl living on your own with your mom, then there was a fifty fifty shot that you were part of that brood.
The twins and Gil were going to have a heck of a time trying to navigate that if they ever decided to try to set up households of their own (although he had a rather nausea inducing feeling that at least one of the twins was of the opinion that it didn't really matter and in fact would only produce a better bloodline).
He didn't have any idea about the identity of his own father although he had heard some whispers that his mother had been married before she came to the Isle. That did not seem particularly like her. She was the kind of crazy that most people did not care to come in close contact with but if his father had been said husband, then he must have lived with them on the Isle for a while. There was no sign of the belongings of such a person in their home. (Of course, completely destroying all evidence of such a person and lying to him about it was probably also his mother's kind of crazy.)
He was reasonably sure that Evie was Gaston's, and he knew Mal wasn't (which really meant nothing except that one of the twins eyed each of them in an inappropriate manner - which made him instinctively protective of his adopted sisters). Jay had literally no clue who his mother might have been (and less interest in even bothering to guess).
Jay was a beta, so being second in command to someone in authority was his nature (and he followed his father or Mal's lead by turns depending on who had spent the most time around him last). Evie was an omega people pleaser of the highest order, and Mal spent the entirety of her life giving no clues whatsoever (which made Carlos pretty sure that she was a beta who lived in daily fear of her mother kicking her to the curb).
In a way, the "invitation" (and that was using the word very loosely - the presumption of giving an order without even an attempt at earning any trust beforehand grated on Carlos's every instinct) was a relief - getting shunted out to do the wicked fae of the Isle's dirty work in the wider world of Auradon had to be better than spending every waking moment trying to evade his mother's ever more blatant power struggle machinations, keeping Jay in some basic sort of order, keeping the girl's from being turned into prey, and keeping the Isle traditional alphas from directly challenging him as a threat (it was exhausting really).
Besides, he wasn't beholden to Mal's mother. He had no obligation to follow the directives of someone that had demonstrated that she was such an abysmal leader (if alphas couldn't even demonstrate proper responsibility in raising their own children, then they weren't the type of alpha that Carlos would give any consideration). He had no loyalty to any of the (as far as he was concerned) failed alphas of the Isle. He would do what was best for his people - no matter what that might turn out to be.
All he needed was a chance at a better offer - one he could lead all four of them into taking.