I've heard from Nerdrotic that that's actually just a Sauron cultist and 'Halbrand' (the guy seen with and seemingly set to enter into a romance with Galadriel in most of the actual marketing for ROP other than all the diversity-centric interviews) will turn out to be Sauron. Even that flies in the face of Tolkien's canon though, since Galadriel was both already married to Celeborn and consistently suspicious of even Sauron-as-Annatar (his angelic 'fair' form) from the very beginning.