So Rayton is the reincarnation of Ethan and I think from this last chapter, Ethan's wish to destroy the monarchy that conspired against him, even though he gave them everything
Due to being this reincarnation Rayton has some of Ethan's powers, so one of them always had to die for the other to live from my understanding. And why Belkiel (I'm sure I ruined that name lol) was so resentful of Rayton (and Setz to a certain degree) cos he knew Ethan 1)was dying and because he knew ultimately Ethan would always choose for Rayton and Setz to get the happy ever after, that he and his former lover never got
Setz is the reincarnation of Ethan's former lover and descendant (after the former lover was forced to have the king at the time's baby [this specific part I'm 70% sure of lol, ).
Hope that helps haha
I actually understood this differently.
Alter ethan was killed/sealed, the first emperor raped Shawarma and when she got pregnant, the emperor thought the child was his and forced her to keep it, but the child turned out to have red eyes because it was actually Ethan's, and Shawarmabmanaged to get the baby out of the palace, then probably got killed. The first emperor held a grudge against Ethan so he insisted that a red eyes and black hair child (aka one of ethan's descendants that will be born from that child) will return to take revenge and distroy the royal family, and probably in time the first king's obsessive prediction turned from a baby that escaped the royal family will return to distroy it into a child from the royal family will distroy it, which is why the last king probably thought that rayton might be his cuz the predistion says red eyes will appear into the royal family. Anyway, so Rayton isn't Ethan's reincarnation, he is his descendant. All male descendants from ethans blood died as children because they all, through their blood, inherted Ethan's power, but were too weak to survive it. So Rayton's annoying mother says she was glad to see he was born with eed eyes, because she kinda knew fron thr ancestors stories or something about that history, and knew that either the child that the last king thinks is his will be too weak to survive the power and die or will actually be super strong and she'll be able to raise him to take revenge for her because why care about the child you had with your actual lover. I hated her if it's not obvious. She also named him rayton because she knew rayton was the name of her god ancestor that died wishing for the destruction of the royal family, in order to force destiny on her kid. Rayton was Ethan's original name, he changed ot later.
Setz is Shawarma's reincarnation, but she is still her own person, and she doesn't fall for the man shawarma loved, aka ethan, but for his descendant, aka rayton, in a way still repeating history. Shawarma wished for 2 things after getting her lover killed, both in case she gets reincarnated, first to suffer and pay for her sins by reincarnation into a royal with blue eyes and golden hair, since it would be painfull to be hated from the start by her lover, and secondly, to be powerless, in order to not be able to hurt him again. In her first life, while rayton isn't ethan, he is the closest thing to ethan, so she is completely powerless to stop him and is hated by him and dies at his hands, but he goes mad and that's probably not what shawarma wanted, so she instinctively uses her powers to turn back time. About the time she returns in time, ethan also gets unsealed, and from begining to end he doesn't know how that happened, so it probably had something to do with shawarma re-getting reincarnated at that moment, we're left to wonder that one. When he wakes up he realises the power he didn't get to unseal drifted into his bloodline, and also that one of the stones he sealed his powers into was damaged and the power was released, meaning the powee that returned to his bloodline and not him, because he was absent, was too much for a human to manage, and was infused with his memories and with the hated for the royals that he felt as he was dying, so he knows that rayton will atract the rest of eathan's power and fo mad from it.

Sooo i read this long ago (the spoiles) and anw maybe my brain not in the right place when i read it but i just dont understand— everything lmao
Partly bc i forgot lots of stuff and im too lazy to read it but as far as i remember
So plz correct me if im wrong
ethan is ethan, but setz isss the lover of ethan(in the past life?) And rayton is rayton. So ethan isnt rayton right?
Butt is it true setz the reincernation of ethan first love??? And why the fuck ethan diedd (i FORGOT like literally plss spoils mee lol)
And why rayton has the power of god (bc i remember rayton isnt ethan)
Goddamn, im sorry if yall confused reading this bc im confused too but anw please spoilss meee!! ( ̄ε(# ̄)Σ