Voidseeker Blade

This stark black blade looks like a starless night sky. When you touch it runes light up its length and your hand becomes as cold as ice. A voice whispers from somewhere far beyond...
It adds +1 to all to hit rolls, +3 against Duergar, Drow, Orks and Goblins, and on a hit it deals regular weapon damage and an additional 1d4 Cold damage. 3 times each day it may unleash Void from its blade, dealing an additional 1d6 Necrotic damage on a hit. While attuned, the user can physically survive temperature