I has a thing for XelFi nudity
Before I begin, a little explanation on how the hell did she actually got Xellos to believe that her naked revelation was nothing but his mind going wild:
She knocked him out and mastered the art of imitating his water elevating spell.
YES THAT'S IT DON'T TELL ME ANYTHING ABOUT HOW THAT MAKES NO SENSE I WILL NOT LISTEN TO YOU LALALALALLA
But then it might have also been that he was following her game
So I came up with this random idea of a sacred "Lagoon of Revelations" in the Slayers' world, where only certain magic creatures can go to find a place of introspection and clarity, being the waters some kind of path towards their hidden necessities and desires.
The thing is that both Xellos and Filia have found a liking to this place, ironically turning it into a war land, and hell did they ended up having some revelation from one another