It had come as a surprise to Skullius.
His basic Null Life abilities – Null Extraction, Static Limbo, Unbound – had completely been removed from his body as conventional skills.
The signs of this odd development had begun during his battle against his alter, the possessed Festos. While being bombarded by the Primary assault of Aphotic Catacomb of the Daemon, his access to all his skills had been cut off, leaving him defenseless, but he had been able to utilize basic Null Life abilities to protect himself with the help of his phantoms.
(A/N: Refer to Ch.1214. You might want to read the whole chapter to get the idea. It's not complicated at all.)
He had controlled Null Life Essence through sheer will rather than relying on the brand of the relevant skills engrained in his body. He had found it odd back then, but time had been tight to speculate.