Ciara

Ciara is a treasure hunter.

The Avatar found her inside the Guardian's dungeon of Terfin in Ultima IX. She was only after money and offered the Avatar a deal: should she get the key to the treasure chamber, she would in turn release the missing cube key (which she had stolen). The Avatar had no choice but to agree to the deal and give her the key.

Trivia

 * Her presence inside the fortress of the Guardian is an insult to logic. She is an obvious plot device.