In the AU I have, Celestia was banished by Luna when Daybreaker took control when she was under massive stress and she was sent to the moon for 15 years. Equestria was now renamed to Eventide Empire and Luna was crowned Queen. During her banishment, technology has massively boomed, alliances were made, armies were growing by the thosuands, and new laws were being written. Once Celestia returned, she was back with ‘mixed results’ of Daybreaker’s possession. Luna expected this to happen, as it happened to her as well.

A few months pass and Celestia has adjusted to the newest changes of Equestria, and Luna has given up half of her Empire for Celestia to rule. Celestia, who was anxious at first, was nervous to take sit on a throne again after the previous meltdown of her mental health from all the nobility and commoners rioting about her reign before. Luna gave her enough confidence to be able to be the ruler Equestria deserves once again, and Celestia has taken her new throne, title, and her Kingdom successfully.