Unstoppable Child Of The Plane.

His major problem here is not death. He is not scared of death at all. What he is afraid of is having the network of Legion exposed to the demon god after his death. This possibility remains because Legion-1 has gone to inquire about demon gods and has found out that anything is possible with a supreme law. 

He is up against an entity with a supreme law so it is possible for his soul to be forcefully assimilated. It is also possible that death will not save him from the demon god. But he hasn't given up. He won't give up until he is dead. 

His best bet for freedom was for the tree father to assist him in breaking through. The supply of divine life energy and his powerful soul will fight against his body. The plan is to cut off his body from his existence. It will kill him, but it will also cause his connection to his body to be severed.