Smargs won't Sing

About three years ago, the village was destroyed by an evil smart (a magical creature), in this case a dragon. The only survivors after the massacre, the sisters of Chloe and Iria, fled to the neighboring village. Chloe's younger sister does not say, but she is a kind and diligent worker who love everything. Elder sister, Iria, destructive, rude and cruel, especially with an unmistakably true chloe. But how did two girls manage to escape from such a powerful creature first? Is it possible that any of them signed an agreement with smarts? [Credit: MH TETHYSDUST]