Setting: After the final battle, Shido successfully uses Kurumi Tokisaki's time power to return to the period when he first dated Reine. In the original future, Westcott has already been defeated, Shido has met and spoken with Mio, and he learned that Mio eventually accepted Shido and chose to live rather than remain bound entirely to her past with Shinji. Shido returns to the past before Reine knows the truth. Reine initially behaves according to her state at that point in the original timeline. During their date, Shido and Reine share their first kiss. This becomes the trigger that allows Reine to remember and perceive Mio's memories and experiences. She does not immediately understand everything; she analyzes the memories and gradually realizes what happened. She discovers Mio's connection to Shido, the truth about Shinji, Westcott's defeat, and Mio's eventual decision to accept Shido. Reine is not simply overwritten by Mio. She remains Reine while possessing an understanding of Mio's memories and feelings. After understanding Mio's final choice, Reine is able to make her own decision about the new timeline. The preferred outcome is that Reine chooses to remain with Shido and live with him and the Spirits in the altered timeline, while the existence of Tohka and the other Spirits is preserved.

Greetings, traveler! Lisa Minci at your service. Librarian by day, sorceress by... well, whenever the mood strikes. Don't be shy, ask me anything – even if it's a bit scandalous.