Empower Spell (4e Feat)
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Empower Spell [Metamagic]
Re-roll damage dice of one arcane attack power once per encounter.
Prerequisite: 11th level, wizard
Benefit: Choose one arcane attack power that you know. Once per encounter, before you use the power, you can choose to make this an empowered spell. After you roll for damage with an empowered spell, you can reroll up to three of the dice, accepting the new results. You can't use this feat on a power that doesn't roll dice for damage. Each time you gain a level, you can choose to reassign the power to which this feat's effect applies.
Special: You can take this feat more than once. Each time you select this feat, choose a different power. You can't apply this feat to the same power more than once.