Board Thread:Theories Discussion/@comment-12376798-20140718225027/@comment-7342272-20140718234901

1) In Servant of Evil, Allen pretty much says he's defying fate and switching places with Rillaine. And the grief of losing her throne, her brother, and everything she ever had is probably a fate as bad as death (seeing as she was a spoiled princess who had/wanted EVERYTHING). If Kayo died as a direct result of her sin, I'm pretty sure it would have been included in her song, seeing that's also the case in the other songs.

2) Ney transplated the Demon of Pride to Rillaine when she claimed the throne as part of Prim's plan. It wouldn't have made sense if she made a contract, seeing as she didn't even know she was possessed.

3) Demon of Pride is noted to have no other powers in it's host other than it's powerful host transformation. One ability it has is being able to transfer through the mirrors as portals, and that's how Ney transplatned the demon to Rillaine. As for the lack of transformation, it just never needed to. If Rillaine was in danger, the demon could have just left rather than transforming. (It'd probably take a lot of energy from the demon to transform, I'm supposing)

4) Rillaine is seen with one of the mirrors in Twiright Prank. This is when she's possessed by the Demon of Gluttony, however. My guess is that Ney didn't give the mirror to Rillaine, she only had it to get Rillaine possessed, then returned the mirror to Prim or Abyss I.R.