Hey Hakuen, I finally had time to get on my PC. Unfortunately, I'm getting this error when testing the plugin. No other plugin is turned on btw. Lmk if there's a fix to this :D 
Hi there!
You need to use my core plugin somewhere above all other Eli Plugins.
https://hakuenstudio.itch.io/eli-book-rpg-maker-mv-mz
If you are already using it, download it again to make sure you have the latest update version.
Let me know if the problem is solved.