Another event you may get when searching the reaches of Kero Fin, you find yourselves granted a chance to have spirit warriors participate in any one battle you lead. This is an encounter in which you have no say; it just happens randomly.
|“||Our expedition to Mount Kero Fin has returned. <X> has a wondrous tale to tell. He and others were exploring the snowy reaches of Orlanth's mother, when they found themselves swept away to participate in an ancient battle, fighting against the forces of Lokamayadon, the traitorous priest who sought to eclipse Orlanth. <X> and the others fought against lancers who fought from horseback. Despite the confusing circumstances and difficult odds, our explorers fought well. Another great gust blew them back to Kero Fin, where wind spirits reward us. They pledged to come to our aid and fight on our behalf against any other clan of Dragon Pass. They would fight one battle only, but would come whenever we called.||”|
When you go into the raid screen, you will find 'Spirit Warriors' as a choice to have help you raid. You should still get all the spoils, and the spirit warriors are good fighters as well.