Beginning at 10th level, you can call upon the ancient survivors of the Dawn War, to bring down ultimate destruction on your enemies. As an attack action, you may make a single melee attack against a target within range of your weapon, dealing damage equal to a number of d4s x half your Warlock level. You are proficient in this attack, can add your Charisma modifier to your damage (instead of Strength or Dexterity), can use your Charisma modifier for the attack roll (instead of Strength or Dexterity) and you can choose the damage type from any of the standard damage types: acid, bludgeoning, cold, fire, force, lightning, necrotic, piercing, poison, psychic, radiant, slashing, and thunder.
You can use this ability a number of times equal to your proficiency bonus, and must complete a long rest before using it again.