Sigfrodr was once an accomplished bard as well as a hunter, but an injury to his vocal cords made singing painful-- he's still a fine oud player, though. Unlike the other hunters, he's taken to staying in Wyvern's Bane year-round, working as a bartender and general handyman for the miners during the summer. He prefers to keep that under wraps, though, and let his fellow hunters concoct their own headcanons for his "adventures."
Wyvern's Bane was one of Brynn's last stops before reaching The Mountain, and his relationship with Sigfrodr lasted through the hunting season. Even after his disappearance and the subsequent rumors of a grisly heel turn, Sig never quite moved on; should he learn of the party's motivations, he'll quietly do all he can to help.