Oh the famous Young Morganthe fight, so many wooly mammoths so little time.
Here is how her cheats work: Whenever you fizzle, cast a blade, cast a trap, heal, etc etc etc she has a chance to zero pip woolly mammoth or even earthquake/supernova cheat cast combo. Also she cheat casts a woolly mammoth on the first turn all the time.
My strategy to avoid all those woolly mammoths, ATTACK
But not any attack, if you get to seventh pips she mana burns you. Meaning only rank 6 and under
Throw in your best 3 sun fist enchantments and your Rank 2/4 none aoe attacks and keep them enchanted every turn (or you can stack your tc with tc enchanted versions with at least monstrous)
Now some of you may be wondering "but wont we need blades and traps?" NOPE, especially if you dont want her cheats triggering.
With multiple wizards you can knock nice quick chunks of her health out quickly. She has zero minions so no need to be worried about aoe spells to go with your solo hit spells.
And congrats, your now 1 dungeon from Azteca :D hope you liked my guide
P.S. she is the only cheater in Ghost Avalon, fight the rest like you normally do