Karyk wanted to come to this world to enact vengeance on the Angels. They were chasing after him and he knew that they were never going to give up until they were absolutely destroyed.
As long as the Angels weren't destroyed, Gabriel and the others couldn't have a peaceful life either. Hence, he came here to kill them.
Even he didn't understand what changed in the process, but the thoughts in his mind were more occupied by becoming a perfect being in the universe.
It was such a strong urge that even the desire for revenge felt small in front of it. He was awakening to his true desires, becoming the one he was born to be.
He rubbed his forehead, sitting in absolute darkness wondering what had been happening to him.
He didn't dislike this feeling, but he still felt a little strange. He felt like he was becoming a different person due to his desires.