^What about KyonxTsuruya?
Well I was watching afk Bamboo Leaf Rhapsody again and the book Nagato was reading in that episode was called
"Time enough for Love". Maybe Nagato really is Ronery, Maybe she wants some luving too? lol
and it happens to esculates when she lives through Endless Eight, which may be the cause for disappearance, although I believe the cause was the fact that she had the future knowledge that she would cause the events of disappearance eventually and it probably ate at her inside as her human side slowly corrupted her... well corrupted isn't the right word but I can't think of the correct term tio use :S.