Black Crusade (2011), p165 — Bone Maul

A common weapon of the feral tribes on The Writhing World, each dull grey bone maul is covered with runic etchings from the world's biomancers and stains of ancient flesh and blood. Each is also much heavier and stronger than any normal bone. With each bloody impact the maul becomes cleaner and brighter than when the battle began, until its foe is dead and it appears as gleaming ivory. After the battle it slowly tarnishes again, until it returns to its original dull grey. This is a two-handed melee weapon.