In order for the god of nobles to solve his current predicament, he can try to fight back and stop the killing of his nobles. Or he can try to fuse completely with his pathway.
He chose to fuse completely mainly because he couldn't possibly fight five high gods who were strong enough to make the god of crime and error, his greatest enemy, retreat.
The second reason he chose to fuse completely with his pathway is that if he succeeds in doing so, he will be able to become a high god. Not only would this improve his strength greatly, but it would also make him immortal, and he wouldn't need to rely on nobles as his foundation anymore.
So fusing with his pathway completely is a very good thing. It will improve his strength and remove his weakness of needing nobles.
All that he needs to make the attempt is to have 10 souls and master his ultimate ability completely. He has met those requirements, so he can make the attempt to fuse with his pathway completely.
