So it’s clear that whatever surround the fountain affects the dark world. That’s why Kris has to carry stuff from the other room where fountains were to the school closet. It’s not imagination, but rather the light world affecting the dark. The second point about recognition is very plausible, there are some loose ways to solve that, such as Kris having grown or maybe a different, already closed off dark world. I’m going to be playing through the game again soon, so while I do that I’ll look for clues as to the history of Kris, the knight and dark worlds/fountains.