Sabrina

Sabrina is a woman who the Avatar encounters imprisoned within the Mountains of Freedom in the time of Ultima VII Part Two.

Description
After throwing the correct lever, the door to Sabrina's cell opens, and the Avatar finds her sleeping on a stone bier. She arises immediately and asks the Avatar to, "Lead me to my nightmare." She is referring to a magical black horse kept in a nearby cell, which she seems to regard as a pet.

If the Avatar leads Sabrina to her nightmare, Sabrina attempts to feed the  nightmare a carrot. This startles the beast, which then rears and calls forth lightning, striking Sabrina dead instantly. On Sabrina's remains, the Avatar finds a carrot, which can be used to solve the next step in the lever room puzzle.

Sabrina also carries a key on her person. The key unlocks a chest in the northwest chamber of the lever room. This chest contains a scroll with important clues to Sabrina's identity. Although the scroll is unsigned, the scroll's author instructs the addressee, who is an "old man," as to how he may be released from the Mountains of Freedom by serving "in my slave pit." Based on this, the scroll was almost certainly written by Filbercio.

The scroll continues with specific and surprisingly compassionate instructions for the old man to care for the nightmare. The scroll also mentions Sabrina by name, cautioning the old man not to allow Sabrina anywhere near the nightmare, as Filbercio fears she frightens the beast, which may strike a person dead when upset (which, of course, is what happens to Sabrina).

From here, the Avatar can make some educated--but unconfirmed--guesses about Sabrina. Firstly, both Sabrina and Filbercio seem to regard this same nightmare as a pet. This indicates that the two had a close, or even familiar, relationship. In the scroll, Filbercio also uses language which may resemble a frustrated father's grudging love for his daughter. Finally, in the original design documents, Filbercio had a daughter. If Sabrina is Filbercio's daughter, she may be the missing "adept's daughter" who caught  Ensorcio's eye.

Trivia

 * The Avatar may spare Sabrina's life and complete the lever room puzzle by creating carrots with the Create Food spell, or by stealing Sabrina's carrots with the Vibrate spell, thus avoiding Sabrina's fatal role in the puzzle.