After an unknown incident leaves Princess Celestia unsure if her precious pupil is alive, dead, or something in-between, the future of Equestria seems uncertain. With the elements compromised, the crown thrown into disarray, and Celestia herself flagging under the weight of her fear and grief, the solar diarch resorts to extra-dimensional assistance to unravel this mystery...

In the form of a lich necromancer.

Inspired by Dead/Light, by Lord Destrustor: https://www.fimfiction.net/story/173638/dead-light