It's gone beyond the point of "Taliesin sold his soul to an elder god" and has honestly come to "Taliesin IS an elder god"
that mysterious figure beckoning you deeper into the dark, offering you pomegranates and red wine, suggesting you sit, just for a moment, just for a meal? that’s taliesin. he’s got great eyeliner and looks like your goth uncle. he’ll teach you the gifts of the fae but also you’re trapped there forever so, y’know, choose wisely and all that