B)How about the twilight element (new thing) or the void? Do they have to do with demons? Only fel does.
Its not about everything that looks cool. Its about a new dark theme that had us hyped with a new tier, several spells being black and white versions of our spells and several Sha whispering in your mind in demonic, similar to how the fel voices work according to quests and lore. On top of it, Sha looks like an immense force, not simply a spiritual thing(eg. Rommath looks ecstatic by consuming some of the essence and compares it to fel).