Erbium was a former princess of Tollund.
Erbium had a tenuous relationship with her sister, Terbium, and once threw a pig's head at her during a royal ball. She also challenged Ash, who was hiding her identity, to speak for herself and reveal who she really was if she wanted to marry Prince Zircon.
After Princess Ash resumed her rightful place as heir to the throne, she stripped Erbium of her royal title and sentenced her to live out the remainder of her life performing hard labor in the peat tunnels. (PROSE: The Bog Warrior)