The Art of We Know The Devil is the official digital art book for We Know the Devil. The art book contains the sprites for the characters, a 40 page PDF of the art as well as the game's CGs and background photos.
Concept Art Edit
The concept art PDF opens with several attempts at writing the title card, written in various styles of pencil and marker on a piece of blank paper. Then the book moves in to Mia Schwartz's first sketches of Neptune and Venus. The book shows several pages of the characters evolution from the original sketches to their final versions, and then begins showing the earliest designs for Jupiter as well.
We then see the first sketches of the characters in color, as well as getting to view the characters heights. Jupiter is 5'3"-5'5" and is the shortest member of Group West, while Neptune is the tallest. Schwartz adds a cosplay note that the colors and shoes are suggestions at best, not set in stone.
The next page is Jupiter's "baby photo gallery", which is a page full of images showing Jupiter's evolution from the sketchy style developed shortly after the original sketches up to the final versions of the sprites. After includes some early attempts at Jupiter's shrug sprite, which were "too sassy" to be in character, but Schwartz believes that makes them cute.
After early Jupiter sprites, Schwartz includes several of Venus's early sprite expressions. Schwartz comments that the reason she has so many Venus screencaps from development was because she was "so fuckin' cute."
Finally we move into some early sprite concepts for Neptune. She was originally going to have a puffball charm on her phone, but that it would have been lost in the UI. Schwartz also shows one of the early devil Neptune sketches, but says she moved away from that concept because she wanted Neptune to look more confrontational.
The PDF book then switches into a couple more "memey" images, including Jupiter Neptune and Venus reenacting a well known "draw your OT3" meme. Schwartz then shows "catalog" charts, or charts of expressions and poses for Aevee Bee to reference while she was writing the game's script.
The book then moves from concept art to art created after the games release, mainly a couple of pages of "shipping" fan art, or pages of romantic art between Neptune and Venus, Venus and Jupiter, and Neptune and Jupiter. There's some more artwork as well, including all of the three Group West girls as cat girls.
Finally, the PDF file contains the CGs from each of the game's ending, including an unused version of Venus's devil.