Sacrificial Xathid Manipulation, as a bonus action, you can spend a hit die to strengthen your next attack (Spells, melee, and ranged)This damage buff comes in the form of necrotic energies dealing an additional damage die, however all the damage you deal from that attack is necrotic. 

Xathid hollows curse: All the necrotic damage dealt from Sacrificial Xathid Manipulation is dealt to you in addition but the damage is cut in half., this damage ignores resistance and immunity to necrotic damage. You also have necrotic resistance.

Notes: Xathid sages were once a great asset to the Empire of Lodrian, they served in the archives, and the heretics eventually dabbled in the forbidden dark arts of the Old Ones. That which is against eternal and unnatural flames, they crafted these rings to give themselves strength..... however it lead to them being hunted and devoured by the Darkeater.