Elyon
If even after all these william is not the prince of darkness, then the author just blue-balled us all along lol. First with the early show of that job class in the trial, second with the goddess of darkness connected to will in all of his lives, then last the statement we hear in the recent chapter. Wait, if the prince of darkness is feared so much, then why is Prince of thunder not given as much as value? Clearly lightning is one of the rarest element along with darkness and I didn't see anyone other than will having that job class.
I’m not sure about William being the prince of darkness, if yes the story will get an abrupt bloodbath or war, like destruction god descending in Hestia and killing all the close friends and family of William, if William is the prince of darkness, i hope it’s not like the elves war arc where he’s was forced to loose some of his humanity to protect them. Please and for god sake don’t put a real human being in relationship with a familiar, you already have Chloe and Claire. It will be dumb as ***** to put Conan with Aila, way to dumb.