Princess Katerina's mother
From Jenny Everywhere Wiki
In the Collapsed Cosmos, Amelia Midnight and Princess Katerina Corwin were separated due to Princess Katerina's mother having placed a curse on her; Katerina, locked in eternal sleep, was placed in a glass coffin until the curse could be broken. (COMIC: The Hermetic Garbage of Jenny Everywhere)
Behind the scenes
This plot point is reminiscent, though not exactly identical to, the ending of the original Snow White fairy tale.