Zayn regained his memories of the past, all of it.
He recalled that he destroyed the last world he visited in order to get rid of the interstellar plague that would have spread across the vast stellar system.
He also recalled every single word the God said to him at that time, "You will understand soon!"
The God had looked like Zayn and he told him that he would understand soon. However, Zayn didn't understand. He felt as if nothing made sense when he first recalled the Zayn-like God's words.
Then again, Zayn recalled the words of the robed man, "You will understand soon.". The robed man who stole the Grimoire of the Ancient, tearing it out of his soul before disappearing all of a sudden said the same thing. He said that he would understand soon.
However, Zayn didn't understand this time either.
Only as the memories of the past slowly came together did something change. It was almost as if the switch of the light bulb turned on.