Faction-wars casualty killed by the Viceroy chief surgeon's brain-cooking spell.
Rosaline is remembered by Tipid as the victim of the chief surgeon of The Madness — the masked Viceroys of the faction wars. The surgeon's spell cooked her brain: her teeth fell out, and the liquid in her eyeballs turned to acid and then exploded over her own face.
Her death is the reason Tipid recoils when Damien tells him his transport to a Viceroy System has already been arranged. Whatever the Viceroys can heal, Tipid remembers first what they can do.
Remembered only through the manner of her death: teeth falling out, eyes bursting into acid.
The example, in Tipid's memory, of what the Viceroys do to people.