Dragon priestess in the birdcage

Summary

"Even though I was supposed to have been rejected for marriage once!?"The Dragon Saintess, tasked with caring for the black dragon "Gramvint," who protects the Kingdom of Elvasti, is the official fiance of the kingdom's prince. The current Dragon Saintess, "Ludia," has dedicated her life since childhood to taking care of the enormous dragon that resides in a giant cage. She was also engaged to the prince, "Edik."However, one day, "Edik" suddenly summoned "Ludia" and informed her of her dismissal as the Dragon Saintess and the annulment of their engagement. To her shock, the new Dragon Saintess was her stepsister, "Leila." What's more, "Edik" told her that her next destination would be marriage to the Black General, "Wilfried." But "Wilfried" rejected the marriage, saying, "You and I are not a good match"!?