Sylvan elves

Faster with magic – that’s nonsense.

Be more gentle, XEL, be more gentle. If you remember, there was nothing at all at first, and the Elements created the world. There are many gods – Scandinavian, Egyptian, Chinese, and others – who, according to legend, created the world. And the same Elemental Lords can restore the world. Or the Guardian himself, using the technology of the Ancients.
You can change not the history, but the concept. Let's say, each race went into its own semi-world. Krigane – into the dimension of hell, Elves – into a parallel world-reflection, the Green Lands, Humans – into the Heavens with the help of angels, Dungeon is half-destroyed but is slowly being reborn, the Swamp into the Swamp Land (a parallel world-planet, completely covered in swamps and inhabited by unseen creatures), mages... either into space or into the dimension of dreams – the embodiment of the thoughts of the inhabitants of the earth, a semi-astral world. However, I would rather see something like this in Heroes 6.

10 million years is also unlikely. If you have to wait that long, they will already be new species with new civilizations, etc.

New civilizations will appear as a result of a grand shift in magical flows during the Armageddon;

The surviving races would not have been saved because the Reckoning struck the Dungeon and the land and the sky.

However, why be so categorical? Mages can easily be saved in the sky/space dimension. Underground – also, although it is more difficult (earthquakes). In another world – 100%;