Leiurus Quinquestriatus, the Deathstalker, a changeling raised to be a living weapon, is left without direction after the Canterlot invasion. Found by The Great And Powerful Trixie, she is taken to the Crystal Empire, in the hopes that somepony will take her in. However, Leiurus was given very specific orders regarding the Crystal Empire...
Orders regarding its destruction...
Part of the rebooted Cricket-Verse, aka The Nonsense-Verse.