As stated already, Black Metal takes the concept of mythic narrative even further than previous incarnations. More often than not, it seems as if the band members themselves are projected through the music into what I personally like to call "amplified beings," or the embodiment of a (generally brutish or malevolent) nature within their being/personality.
One good example might be Evil of Marduk. By all accounts I have heard, Morgan Håkansson certainly does take his music seriously onstage and off, but of course has an "outside" human life just as anyone. However, Evil would then solely be the demonic, war-scarred guitarist for Marduk, brought in and out of this plane during set rituals.... Performance, Recording, ect. This is at least one major function of corpse paint, "stage names," and the like.
In that respect, Dead and arguably Euronymous are examples of the danger that lies in this exploration.
I know little about Antaeus more than the CYFWS album, but one could probably assume such a general outlook. Ultimately, it comes down to the music itself. This is, like many things, all observation.