Hua Taixu used the cycle of samsara to save countless lives, allowing them to have a chance to cultivate again in the next life. He spoiled the grand plans of the Buddha Sovereign. The faith of countless people in the western world army was used by the Grand Devil Lord as he battled, granting him immense might, allowing him to hold his own against three.
But now since the majority of them entered samsara, the strength of the Grand Devil Lord was greatly reduced. He was left with his original strength.
The Buddhist Sect traveled east. Why did the Buddha Sovereign bring the Buddhist Sect with him to fight the Heaven Vault? Obviously, he wanted to use the faith they provided, converting it into his strength. Sadly, all of his plans were spoiled by an ex-buddha lord of the western paradise.
Buddhism speaks of karma, wasn't this a karma of sorts?