Master of Elements is a popular PvE talent for any talent build with more than 15 points in the Fire tree. It restores up to 10/20/30% of the mana cost of a Fire or Frost spell that critically hits one or more targets (so AoE spells such as [Flamestrike], [Cone of Cold] and [Blast Wave] are affected by this talent). Since most mages critically hit between 20 and 40% of the time this talent is equivalent to an effective mana cost reduction to Fire and Frost spells.
[Flamestrike], 
[Cone of Cold] and 
[Blast Wave] are affected by this talent). Since most mages critically hit between 20 and 40% of the time this talent is equivalent to an effective mana cost reduction to Fire and Frost spells.
