In the Upper Halls in Darkmoor where you fight Shane Von Shane you can find a few books you can read. One of the books is very interesting and I feel may give us some insight into Arc 4. The book says..
"These two volumes are entitled House of Secrets and House of Mystery. There are two houses in Darkmoor where secrets breed and mysteries bloom. These are waystations on the frontiers of nightmare. One is home to the unknown, the other to the unknowable. Their rooms are endless. Their halls, infinite. And their masters and mistresses, everchanging."
I wonder if these books have anything to do with "Nothing" and the Abberant Paradox we meet in Karamelle. Will we possibly revisit Darkmoor in Arc 4?