My Noble Magus

Rhain was a powerful magic user in a world where that was rare. Because of this, she was sought after by the Duke of Tyvern to become his duchess that way when he died, someone would be left behind to protect the secrets of Tyvern until the heir was of age.
One month before Tyvern's leadership would be passed to the heir, the dukedom was attacked. Rhain defended the land as best as she could, but she was defeated in the end. In her final moments, she used her magic to destroy Tyvern's secret- an ancient artifact. Instead, she activated it. She was sent back in time to two years before the attack.
This time, she will succeed in defending Tyvern. Maybe this time, she'll find happiness while she's at it.