From Labyrinthe Wiki
Purgo Palmura was one of the Legendary artefacts of Alleria, it was a spirit of fire bound into, normally a sword but over the years has been bonded to different weapons. It was rescued by a Lucas Belphebe, and lives within his normal sword, and can take over its form turning into a sword of pure flame. The sword would always catch a flicker of fire in the prescence of creatures of evil or undeath, and would always know where they were, even if hidden, and would burn away it's foes.
A few years later whilst Lucas was engaged in the war effort against the Myronese he captured a vial of ground Dragon Ore. This potent substance was applied to the metal of Lucas' sword and where once Purgo Palmura had been a creature of pure spirit, it was now bound with magic. Further, this allows Lucas to somehow bind his miracles with fire magic. There are some who would argue that this is a trifle silly (Lucas himself suspects that if he carries the sword about much longer, it will end up gaining druidical powers).