The Arsenic Fang was the bone-white dirk wielded by Duke Lucius Errikale during the Wars of Succession. He drew it during his fight with Lucaine Pyramides at the Battle of King's Tomb, but did not have a chance to use it, as Pyramides shattered both the Arsenic Fang and Errikale with his Desperate Angel technique. As the dirk broke, it sprayed poisonous acid over the remains of Errikale's body.