Erky Timbers was a mysterious, demented devotee of Selune who was rescued from the Moonless Citadel by the Lunar Legends in 1611. He joined the group on their adventure to take down the evil Gulthias tree and return to Lunasett. In an attempt to heal the blighted victims Erky heroically sacrifices himself and shot up into the sky to become a tertiary moon.
This same moon was destroyed by an alien spacecraft around 1687.