Literally all they do is spam tower. If you're Ice and going through this I feel bad for you. These are poorly designed AIs that basically waste your time. A way to counter them is to use constant DoTs, though. Ice wizards like me, even at level 72 playing this, are just naturally having a hard time. I managed to win my first battle with them in about ten minutes, so we'll see if the record continues
I agree. Frost Bones need to be nerfed in general, but at least you aren't balance. On my balance, Wintertusk was the bane of my existence. I still think that balance needs a DOT to counter tower shields.
For balance, think of hydra as an "Instant DOT". Three attacks that go off the same turn, and burn tower shields separately. Combine with balance blade, elemental blade, elemental trap.
For ice, start with balefrost, then spam frostbite, with whatever blades you can use.
Either way, consider getting an enchanted armament pet, the sharpen blade spells give you effectively more stackable blades, which are very helpful.