Black Malice

Black Malice is a two-handed mace that has a Shadow proc and additional Shadow damage.

Made entirely of thorium, this massive mace is intended only for the strongest of wielders. The weapon is extremely large and heavy. The mace is entirely black in color, save for silver metal spikes jutting out from the thick, evil-looking head.

Source
This item is a rare drop from trash mobs in Shadowfang Keep.