Blade of Death

You pull a blade of dark energy from the shadows around you. This blade is a finesse martial melee weapon with which you are considered proficient, and can use your spellcasting ability modifier instead of dexterity or strength. It deals 3d8 necrotic damage on a hit, and if you hit a creature in dim light or darkness you deal an additional 1d8 necrotic damage.

When cast using a higher level spell slot, the weapon’s base damage increases by 1d8, and the additional damage increases by 1d8, for every 2 slot levels higher than 2nd.