Untererde Battlemage

Whenever Untererde Battlemage deals combat damage, put that many charge counters on it. Then, if there are 10 or more charge counters on it, transform Untererde Battlemage.
Remove a charge counter from Untererde Battlemage: Prevent the next 1 damage to target creature or player.
"Why is it shielding them? I thought demons liked being reckless!"