Soaring Will

 Soaring Will  is a trinket-exclusive rune in Villagers & Heroes.

  

Acquisition
 * The value x is dependent on the level of the rune that the spell is coming from.
 * Activate to have the next 3 spells you cast cost 0 Mana and increase your Will by x for 20 seconds.
 * Available at level 35+.
 * This trinket rune is specifically good for classes that are burdened by expensive spells.