Flamesword

The Flamesword is the most infamous of the Weapons of Light, used by Mardar Valamentar to strike down the Dark God in 2147. When not Ignited, it resembles a normal longsword, with a black steel blade. But when cast, the blade sets fire with an eternal flame, powerful enough to destroy any known object or to penetrate any magical forcefield. It is the only known weapon capable of damaging or killing the Dark God. Its current whereabouts are unknown.