Master of Elements

Master of Elements is a popular PvE talent for any talent build. It restores up to 15/30% of the mana cost of any 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 of all spells which can critically strike.

This Talent is especially good for high level arcane mages, as the mana conservation means more spell damage increase from Mana Adept.

For channeled spells that deal damage in ticks such as Arcane Missiles and Blizzard, the mana returned is based on the tick that critically hit, and not the entire spell. For example, Arcane Missiles in its higher levels deals damage in 5 ticks: it will only return 15/30% of 1/5th of the cost of Arcane Missiles and not its total. However, because these two spells have high mana costs, Master of Elements can still go a long way in conserving mana for a mage who uses either.

Prior to patch 3.0.2, Master of Elements only affected fire and frost spells. It was changed in that patch to affect all mage spells.