I generally go with "Uncounted aeons," and in the context of the now-no-longer-relevant Dreams of the First Age timeline (which I wrote), that easily translates into "Millions of years at least, probably." It depends on how long you think an aeon should be, and how many of them you need to have before it's poetically useful to start describing that amount as "uncounted."
Significantly more time passed before the Divine Rebellion than has passed since, though. The history of humanity's time in Creation is a punctuation mark at the end of a very, very long story, now almost entirely lost -- in part because of the actions of the Exalted during that war. Their actions would seem less momentous if they, with their overthrow of the enemies of the gods, hadn't put an end to a span of history of so great as to stagger anyone who contemplates it.
Originally posted by Prometheus878
Naturally, degenerate survivors of these untold eons lurk in the forgotten places of the world. Whatever resemblance they bear to humans or near-humans is misleading, and they howl with ancient fury for the blood of their usurpers' inheritors, the modern humans and exalted.
Bloated, warped patriarchs of reptilian, amphibian things crouch on stone thrones, cataract-clouded eyes creaking open to pronounce blood feuds against our heroes; vengeance ages overdue for the fall of empires that were old when the world knew not green grass or blue sky.
Expect mountains with a high chance of madness.
(But consider also: Clarke Ashton Smith, who even Lovecraft thought was better than Lovecraft at similar subject matter.)
(In all seriousness read Clarke Ashton Smith's The Eternal World
and then think about how to apply it to descriptions of beings such as the Yozis. It's short!)