A Onceler x Reader Fanfic

What if the Onceler had an Assistant? What would their relationship be like? Would The Onceler's fate change? (I'm playing around with some ideas here so please be patient and kind. This is my first fanfic.)

Equity

A prisoner with a life sentence meets a mysterious man who offers him a way to escape--a means to be free--anytime he wants, in exchange for a small favor. But at what cost?