Erebus is technically in-universe of FHome AU but he’s irrelevant plotwise? Nyx’s lover who lives halfway across the world and they just have passionate moments every few years and only keep in contact via letters. Old fashioned. 

Knows he technically has kids but he and Nyx decided its just better that he’s not around. Charon and the twins haven’t even ever met him and they don’t mind/don’t care.