Shortly after turning eighteen, Riet made a very foolish deal with the Ricksian Cult of Mephistopheles. This deal was for magical power--not in the traditional sense, but to gain her entrance to the Academy, where she could cultivate her own skills. In exchange, when her education was complete, she was meant to return home and work with the cult, advancing their aims within her home city--the heart of an old and decaying empire.
Naturally, a few days before she was set to "complete her education," she faked her own death and fled west.
A few weeks after her departure, her eyes began to change. Her irises turned a bright yellow. They began to expand, swallowing up her pupils or sclera. They began to glow, faintly, like cooling metal. She recognized this for what it was. Maybe there was fiendish blood somewhere in her family history, and the influence of the contract had drawn it out. Maybe the attempt to exploit that loophole had been enough on its own. Either way, she was marked by her heritage, now, and that would make it very difficult to hide from her debtors anywhere in the Old World.
Fair enough. She'd go further. The new world beckoned, and beyond it, a sea of stars.