A world god can freeze him and prevent him from resurrecting forever. Even an Origin god is not safe from a world god much less him. He is not a naive fool to think that the sage won't betray him when they meet. The sage doesn't even need to do it himself, he could have arranged for someone else to kill him after he leaves the plane.
Anything can happen to him when he leaves the safety of the plane but he doesn't have an option. He has to go despite the fact that he dreads the meeting. He can't avoid meeting the first sage because the things he negotiated for can not be brought safely into the realm tree.
