If i had to come up with a theory on why emilia was gone, i'd guess that satella manifested in the temple and was feeling jealous with. And because subaru doesn't seem to confront. Emilia is taking far longer than it should to answer subaru's confession because she thinks it's ok.
Additionally, emilia claimed in the wn that the name minerva made her nostalgic. A compilation of evidence that emilia's mother is minerva. That's where emilia and subaru come in.
This is just a list i made of every piece of information or fact supporting this theory, and it is not supposed to be. Emilia was frozen when she was 7, not 15. I think emilia would have woken subaru in that case. Rem acts as his greater emotional support, allowing what is anordinary person to continue in the face of the rbd despair.
Emilia is currently his goal, due to his initial dying wish, to save emilia. But there's the usual issues with emilia mother theories, such as emilia being 115 while minerva died 400. Her mental age is 14, which includes the six years she spent in elior forest with puck and the single year she was at roswaal's mansion before. Comunidad donde se comparte contenido multimedia de la hermosa emilia vizcarra.