Energy Attunement (Su)
At 5th level, as a free action, a magus can spend a point of his black blade’s arcane pool to have it deal one of the following types of damage instead of weapon damage: cold, electricity, or fire. He can spend 2 points from the black blade’s arcane pool to deal sonic or force damage instead of weapon damage. This effect lasts until the start of the magus’s next turn.