So i've got a huge theory which places all the puzzle pieces on their right spot.
- Subaru is Flugel BECAUSE : It is highly implied and all those hints have to mean something with Subaru = Flugel. Even Shaula smelled him!!!! Also, this theory takes place during Arc 10-11, i think that subaru has at this point all the Witch Genes
- Emilia is Satella because they look identical and she does show a relationship with the Witch.
- 1. Subaru and Emilia go back in time somepoint and he gets back to a moment where Emilia takes the Witch Genes of Envy and becomes Satella. Losing all her memories and forgets her self because Subaru ate her memories with his Witch Genes of Gluttony
- 2.Then something Happends and Subaru has to leave Satella/Emilia for some reason for a time being.
- 2.5 Somewhere in the meantime when Subaru ate Emilia and inbetween he sealed her, Subaru met Petelgeuse and gave him the "Bones of Flugel" Which we're the Sloth Genes he had to give away for Some Reason.
- 3.Subaru then returns a time later along with Volcanica and Reid (which he recruited during Arc 10) and seals Satella because Satella started to become insane because she couldn't bear the pain of the Witch of Envy personality. Subaru/Flugel couldn't see Emilia/Satella suffer that much and sealed her.
- 4.5 This would explain why Satella loves him and maybe something happend between Flugel and the new Satella (amenestic Emilia)
- 5.Subaru then plants the Flugel Tree BECAUSE He knows he will need this tree for a fight against the Hakugei (Arc 3).
This would make a lot sense. :) THIS SERIOUSLY makes soooo much unexplained things better!