:This is how I get the ending. The queen who originally sealed the demon king is really June. Because she loved Sejuru, she wanted him to experience happiness as they did when they were children. So she sealed his powers, turning him into a child and she brings him immediately to the past where they first met. Then the events flowed as they are in the manga until Sejuru finds out that he is the demon king and June becomes the queen and the cycle repeats. Well, that's how I understood it.The meer I think about it, the meer sad I become. June, she's still just a kid. In order to grant Sejuru happiness, she made it so that she ;watched over him her whole life, even though Sejuru will never realise what has happened, and the two will never truly be together, and towards the end, Sejuru even forgot about her for a long while. And June, she will forever only be able to live just those few years, her life ending before she can achieve even the beginning of happily ever after.