Crystalline Skull

The bearer starts with a power reserve of 0. Each time the bearer successfully casts a spell that is not unbound, increase the bearer's power reserve by 1. Once per battle, in your hero phase, you can say that the bearer will shatter the crystalline skull. If you do so, pick 1 enemy unit within 12" of the bearer and roll a number of dice equal to the power reserve. For each 3+, that unit suffers 1 mortal wound.