IIRC, Stepmama From Heck woke Kou up to be her flunky, but she and Lirin hadn't been imprisoned. (I remember this because of an author's note saying not to take Lirin lightly because even though she's little and cute and spunky and hyper and childlike, she was awake those 500 years, and Kou wasn't. Which has always made me wonder if the Lirin we see is Lirin trying to be the sister he remembers, or if she's trying to be someone she used to be because she was happier then.)