Bellona was an Ancient Roman war goddess. She is believed to be one of the numinous gods of the Romans (without a particular mythology and possibly of Etruscan origin), and is supposed by many to have been the Romans' original war deity, predating the identification of Mars with Ares. She accompanied Mars into battle and is taken variously as his sister, wife or daughter. She is also (as at her temple in Ostia) syncreted with Magna Mater.
Bellona's attribute is not a sword and she is depicted wearing a helmet and armed with a spear and a torch.