Yavor

Once an eneny of the Storm Tribe, now one of Thunder Brothers
 * One of Fire Tribe warriors, called Great Fulguration
 * He cut off Umath's head after Jakrekriand killed him
 * Orlanth cut his head off, and imprisoned his parts as most powerful weapons: Gutburner, Treeburner and Stormspear
 * After Orlanth's departure, Elmal acknowledged as a kinsman
 * After the Dawn, Orlanth and he made a peace

Maybe he is the weapon that Orlanth robbed Yelmalio in the Hill of Gold in the monomyth.