Here are some concept arts that we found at Pixiv.net
artist: Nenchi Komitore No. 4 software 17b / ねんち コミトレ4号ソ17b
The artist also provided not only the Char's Color but also a Stein color! amazing isn't it?
artist: Nenchi Komitore No. 4 software 17b / ねんち コミトレ4号ソ17b
The artist also provided not only the Char's Color but also a Stein color! amazing isn't it?