Having no means of killing Bjørn the Behemoose, Rodolfo Briscoletti created The Pothold with the intent of sealing away the oversized demon. The blue light emanating from the jar within indicated his efforts to be a success, though as Rodolfo suspected it wouldn't hold him forever.
Centuries after, his descendant Rodrigo Briscoletti continued keeping an eye on The Pothold. Additionally, if The Hero marries either of his daughters, Nera or Debora, he is asked by Rodrigo to check on the jar with his wife before she can journey off with him. Upon checking it out, there remains a blue glow.
Several years later, a merchant traveling to Mostroferrato discovers an eerie red glow coming from The Pothold. Upon mentioning it in town, Rodrigo is panic stricken and asks the recently unpetrified Hero and his party to check it out. They do so with the result being Bjørn shortly breaking free afterwards.
Despite his might, The Hero and party successfully defeat him in battle, resulting in him returning to the jar.
After recruiting Starkers, The Hero and his party can return to the Pothold to recruit Rebjorn.