Egypt is the dream for mine. I've always been fascinated with their mythology and the near endless stories that are told that can be drawn upon. Anubis, Set and Ra in particular are brilliant dynamics with Kratos and Atreus waiting to happen (GoW 2018 spoilers:)
Hindu is a close second, just for how batshit it could get, especially in the context of a GoW game.
especially when Atreus gets closer to his Loki persona.
Hindu is a close second, just for how batshit it could get, especially in the context of a GoW game.