It most certainly is fantasy.
But it’s heavily laced with real occultic imagery and themes. And, for the most part, it presents this material in a neutral, judgement-free way. Occultism is not a game - it can utterly ruin lives. I have seen it do so.
What real occultic imagery and themes? I mean really, not just what stupid D&D playing wiccans take from Greek mythology.
There is a difference between occultism and fantasy magic. One is waving a wand and yelling “Wingardium Leviosa” and the other is sacrificing virgins on a pagan altar. Neither accomplishes much but the second leaves more scars.
No, it's mostly a mish-mash of Greek & Roman myths, Star Wars, and bad Latin.