The intense pressure caused the immortal power in Nathan's body to constantly boil; just a little more and he would be able to completely control it, not just relying on instinct to call it like now.
The same goes for demon power; the process of constantly fighting close combat made his body stronger and stronger, almost comparable to some demon beasts with strong bloodlines.
Of the six types of living beings' power, only demon power was at his disposal, simply because the environment in the Desperate Demon Abyss was mostly demon energy. In addition, when the living beings' blood merged with the Eternal Life Body, the demon energy contributed more than four parts of the power. But Nathan did not want to rely too much on this type of demon power. Since he woke up, although he had temporarily sealed the heart demon, it could return at any time.