Darkfire Strike

Guided by whispers from the shadows around you, dark magic begins to build, igniting your weapon in a purple-black flame. You make one attack with the weapon used in the spell’s casting. The attack uses your spellcasting ability for the attack and damage rolls instead of using Strength or Dexterity. If the attack deals damage, it can be Necrotic damage or the weapon’s normal damage type (your choice).

Cantrip Upgrade. Whether you deal Necrotic damage or the weapon’s normal damage type, the attack deals extra Necrotic damage when you reach levels 5 (1d6), 11 (2d6), and 17 (3d6).