Prefrey was a High-ranking Superior and Frey's biodata donor. After Chris Cwej negated most of the Cwejen Uprising, she negotiated with Cwej-V and accepted his demands to no longer work for the Superiors, so long as he did what he could to make ammends for the destruction he caused. (PROSE: Rebel Rebel)
Behind the scenes
It is heavily implied that Prefrey is an alias of Romana.