Brother Tomas transformed Clayton and Engadine into creatures for the use of the Brotherhood of the Immanent Flesh. They were sent to infiltrate Montague's group. He discovered their purpose and made them into his servants.
However, she was later able to break free from the programming for long enough to shoot Montague. Distracted because he was dealing with a Quoth conflict, the bullet was able to strike and kill him. (PROSE: The Death of Art)