Spoilers . . . . . . . . . . . . . . . . . Based on the novel spoilers, Sir Mio is said to die in the fantasy world but at the end Ash takes him to her world just before he dies. So it is assumed that he survives. She also goes back to her world and Klein (the ML) goes with her. But apparently it is a harem ending since the two other male leads (the magician guy and Mio) go with her too eventually. You can read the spoilers through novelupdates, here is the link:
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Based on the novel spoilers, Sir Mio is said to die in the fantasy world but at the end Ash takes him to her world just before he dies. So it is assumed that he survives. She also goes back to her world and Klein (the ML) goes with her. But apparently it is a harem ending since the two other male leads (the magician guy and Mio) go with her too eventually. You can read the spoilers through novelupdates, here is the link:
https://forum.novelupdates.com/threads/surviving-as-a-maid-시녀로-살아남기.113713/