Apologies as I am not playing the game at the moment, but is it explained anywhere where the other eternal ones are during the events of Sanctum of Domination? In particular, why do they not defend the Arbiter during the Sylvanas fight?
Presumably the Archon is still recovering from her wounds, but given the Primus' constant warnings about not letting the Jailer obtain the final key I'd think he might at least make an appearance.