Zhang Yi wanted to help with something else until the time of the war, but it was impossible for him to reach the Eternal Realm without at least waiting 500 years, and he needed at least 100 years to get Dao in another law that he understood.
Zhang Yi used the soul search technique on all the demons that died and thus got even more information about the demons, but these demons had no new information and only reinforced some of the things he knew.
Zhang Yi brought all the beasts back into his mental energy world and so they went back to the distorted timeline to fully recover their qi so that they could attack the other underworld and kill all the demons that were in the underworld.
