Looks like a personification of the purple robot (Cookie?) of Majikoi S.
I don't know if it's just a fanmade personification or an actual girl version of it (never played the game and didn't find anything about a human form). If you google that one pixiv tag クッキー第四形態 there are some more pics of her (something about a TCG?). Don't know shit for japanese so I have no idea besides that.