As for the Sensibility Demon, before he could defeat it, the two demon natures switched places.
The Sensibility Demon took control of the body, while the Rational Demon entered the Thought Palace to duel him.
He defeated that wicked little brat, yet could not awaken, clearly because his physical vessel no longer existed in reality.
There are two possibilities: one, he is truly dead, his body completely obliterated.
The other is that he likely underwent Plantification, rendering him like a vegetable without consciousness, only instinct.
He had planned for this in advance.
As soon as the Angel Envoy is summoned, Solomon will help him hypnotize the Demon Tree.
Being deeply asleep is actually scarier than being dead.
If he were dead, he could still move within the Thought Palace, but asleep, he's truly asleep, even the consciousness in the Thought Palace rests.
At this point, the Sensibility Demon and he both fall into slumber, headed back to restore Heart Power.