Clean UI is a mod for Dark Souls II, created by Bottle.
This mod makes most menu screens and popups in the game (semi-)transparent. The author tried to change as little as possible, basically this mod removes the leather-/book-page-backgrounds from most screens and prompts.
How to use?
You NEED GeDoSaTo! set texture override to true in its config file.
Either use the Nexus Mod Manager or manually uncompress the archive to GeDoSaTo_location/textures/DarkSoulsII/override.