Disruption

You can place an unholy ward on yourself. Until the spell ends or your concentration is broken, any creature who targets you with a melee or ranged attack with a weapon is forced to make a constitution saving throw. On a failed save, the creature takes 1d8+1 necrotic damage every turn for the remaining length of the spell's duration. This spell doesn't protect the you from spells or area effects, as such those attackers do not make the constitution check. The spell ends when another spell is cast.

At Higher levels: The spell's damage output scales by 2d8+2 every two levels. (1st-level: 1d8+1, 3rd-level: 3d8+3, 5th-level: 5d8+5, etc.)