Dark Blade Strike

You concentrate Shadow magic around your weapon, charging it with power from Darkness, but its a taxing excercise...

For the Duration of the spell your melee weapon deals 2d8 extra psychic damage on a hit . In addition, when you use your weapon to attack a target that is in dim light or darkness, you make the attack roll with advantage.

When the spell ends, you gain 1 point of exhaustion.

You can use this spell Once per Long rest.

At Higher Levels. When you cast this spell using a 3rd- or 4th-level spell slot, the damage increases to 3d8. When you cast it using a 5th- or 6th-level spell slot, the damage increases to 4d8.