She is one of the daughters of the three families. She is a recluse who lives a nocturnal lifestyle, and goes out of the house only at night. While blunt and curt to a fault, she romantically considers herself a “princess.” Five years ago, she was taken away by spirits, and she has never told anyone.
When Rinne was 18 years old, she had a fight with her father about the “first” Setsuna. Rinne and the first Setsuna went out to sail to get away. A storm appeared and threw the both of them into the sea. They somehow drifted away to a mysterious island, waking up there. On this island they started building a relationship, growing really close. Setsuna would later find a “Time Freezing” - capsule. They knew they wouldn’t survive much longer on the island due to lack of food and resources. Setsuna tells Rinne to step into the capsule, where she then gets put into a hibernation state where time is stopped. 5 years pass, during this time Setsuna passes away, doing so happy, knowing he had saved the person he loved.