Treasure of Woe

Series One
The Treasure of Woe appears in the fourth book, when Jonny attempts to remove it. The Mind Sword's voice prompts Jonny that he is not the one to remove it. Jonny cries at hearing the Mind Sword's voice, and realizes what the treasure that only he can take is.

Series Two
The Treasure of Woe is taken by Romus, who is supposed to bring the treasure back as atonement.