Explanation of "The Warp"

This will be fun.

Setting: A Magic Book, Anachronistic Time Era

Yes, a magic book. characters are warped in from their respective settings with broken memories of their origins. This can be a character with origins in any lore, setting, myth, game, or idea. This character cannot be a canon character, though.
(Example: You CAN have a human Jedi from the Star Wars universe but he CAN'T be Luke Skywalker.)
Other than that, nearly anything goes.

The book itself is a collection of "pages" to form a great plain of "paper". Some of these areas have towns, plants, animals, and geographical features "drawn" into them, while other areas are a flat page. Occasionally new "drawings" will appear in these blank areas.

The book has cycles of day and night similar to earth, with the exception that night and day are universal inside the book. (There won't be some places that are day and some places that are night.) The blank pages are extremely dangerous during the night, because there is no source of overhead light (no moon/stars) and the aberrations appear.

Aberrations are horrors created by "The Author" who wander the blank pages and attack the very existence of whoever is unfortunate enough to be caught out at night.