This step was something Chen Yu had already walked through in the past, and he had even integrated his very first Demon Soul. It was only later, when the Demon Lord led the grand demon army to invade the human race and sparked the great war among the humans, monsters, and demons, that things changed.
Then, the Lesser Western Heaven opened completely, the Human King Chuyao manifested in the world, and coupled with the Heavenly Giant Clan heading to the Primeval World to harvest souls, Chen Yu simply had no time to continue integrating his other Demon Souls.
Later, upon entering the cosmic world, Chen Yu completely abandoned the dark demonic power and stopped investing any effort into this path.
Chapter 2692