So we got the Curse of Osiris trailer today, and at the end when we're shown the release date we also get a peak at the poster for the next expansion - the one we know features Warmind involvement. If you look closely - or watch My Name is Byf's short news video where he enlarges the poster - you'll see that the female guardian above the Warmind door has an Iron Lord symbol on her shoulder. At the very least this guarantees that we'll see SIVA in the second expansion. The colonizing-tool-turned-super-weapon is what connects the Iron Lords to the Warmind in the lore we already have. But if this female guardian is a true Iron Lord then she has to be Lady Efrideet in new armour. This may mean that this is the expansion where we come into contact with her secret community of pacifist guardians.