The monster was just made from chaotic energy mixed together so there was no comprehension or complete rune he could absorb for himself. But still it became a pretty good supplement for him.
Devouring the whole head along with the body, the only thing left was its eye, lying on his hand just floating a millimeter above it.
The fight outside had gone for quite a time and had reached its peak where even a tiny mistake could result in your whole life being taken away. So he had two choices for himself. Either not absorbing this eye and digesting the things he absorbed which would result in a more solid base or absorbing this eye right now and making an unstable base.
If he were to choose logically, he would choose the former option but he now had a very strange desire that was telling him to absorb this eye right now or else this chance would be gone forever.
