Impossible, Mage - No unit loss.

[DGDobrev]

That's why I'm giving armageddon info. Fire rain will toast pretty much everything that doesn't have fire resistance and will obliterate thorns, ents and such, because the have fire vulnerability.

You can refer to this site for additionnal info about the chaos spells basic damage:
http://www.gamebanshee.com/kingsboun...pellschaos.php

Also that 1800 damage is the bast a mage can show for without the intellect and item bonuses. It may go higher, but on impossible that damage isn't much, because you're generally overpowered, and 2xarmageddon will have you out of mana in just a few turns.