Even though the Demon Ancestor didn't completely possess Zepharis, he could still see some of Zepharis' memories.
Of course, even those memories, he was unable to digest completely because he was busy with attacking Kaelthar at first, then Ethan, and later trying to run away.
In the end, he had vaguely seen some of Zepharis' memories.
Especially the recent ones…where Ethan possessed Godly Artifacts that helped thousands of Night Demons with their cultivation and cultivation techniques.
Moreover, through Ethan's actions—such as giving a Godly Comprehension Fruit to Zepharis, which directly upgraded a cultivation technique's mastery to the Transcendental Stage before entering the Demon Wolf Realm—Morveth knew that Ethan cared a lot about Zepharis.
Otherwise, why would he give such a valuable item to a Demon Core Realm servant?
Thus, he decided to use Zepharis' body to negotiate a way out with Ethan's help.
