From Halopedia, the Halo wiki
A gravity mace is a hand-held melee weapon most prominently used by Jiralhanae. Atriox, warmaster of the Banished, uses a gravity mace called Chainbreaker, which he hand-crafted out of parts from a gravity hammer. Atriox's lieutenant Decimus also used a type of gravity mace built into the right arm of his powered exoskeleton.
List of appearances