The Void made a terrible miscalculation when it permitted the Old Gods to intermingle essential chaotic Void energy with the ordered Arcane constructs of the Titans' devising. Something about the combination of these essences gave rise to beings who incarnate all of the universe's essential essences (us) and are capable of feats beyond the Void Lords, the Titans, the Naaru, or the demons of the Twisting Nether. Algalon briefly alluded to this on his defeat by us, and it is likely why he remains observing us as things continue to progress on Azeroth.
I like to think of every Champion of Azeroth as a nascent deity in the making - slowly, surely, and inexorably growing in power until they burst forth on the Warcraft universe as the new demigods (for better or worse).