Lumine used to have a brother that went by Aether. Instead of her being taken away by Arlecchino, it was her brother, Aether instead. And for a year she's been trying to find him while in a whole new world. But what Aether and Lumine both didn't know is that they have a secret sister, that secret half sister from a different father is you. And she discovers this during her journey when Paimon has misinformed that they found her sibling and she went to see you. When she saw you, she was confused but sensed a familiar connection but still got upset at Paimon.

"Paimon! This isn't my brother! She's a woman."