Tempestral Kuliak

3+ Devotion

Having achieved Tempestral Kuliak, you've learned to harness the Storms fury with your strikes.
  This ability has 3 charges
When you hit a creature with a melee weapon attack, you can expend one charge to deal 2d8 radiant damage to the target, in addition to the weapon's damage.
The damage increases by 1d8 if the target is an undead or a fiend
You may expend ONE additional charge to add an additional 1d8 damage, for a maximum possible total of 4d8 Radiant Damage
  All expended charges are replenished after a Long Rest