|Charge up and BOOM!!!|
Enemy Ability: Blast
Releases all charges and deals damage to the targeted hero. Each charge buff greatly increases the damage dealt.
Self Ability: Charge Up
Gains a charge buff which lasts for 4 turns. Charges can stack to increase the damage of the Goblin Mage's attack.
The Diverter can negate this monster almost entirely through his Shatter ability. Use of Knight 's Protect along with untargetable abilities is a good way to prevent the mage from one-shotting a hero.
If defensive measures can't be taken, it's best to kill the mage before he charges up and becomes dangerous. His low Armor makes it relatively easy.