Making an oath with his divine fragment and the authority of another pathway means that if he breaks the oath, he will lose his divine fragment, fall to the level of angel and die because his existence is incomplete.
It is the divine fragment that is keeping him alive right now. Without it, he will die.
But if he somehow survives the loss of the divine fragment, the authority of the god of disaster will strike him and kill me to make sure that he dies for breaking the oath.
So this oath matter is very serious. Once he makes it, there is no going back. Even if he becomes a god and breaks the oath, he will still have to pay a heavy price for doing so. But the half God of killing didn't refuse.
Not that he had a choice in the matter right now. Since he has reached this point with the god of nobles, he can't quit anymore. He has to swear the oath, or he will be destroyed.
