I found this mini-doujinshi years ago and my hard drive got wrecked, and now I can't find it again. If I recall right, it used to be on Pixiv, and there was an image of Serena (a custom one with the long twintails) and a Delphox, and she looked disappointed/upset, and I -think- the image was purple. The doujinshi itself wasn't r-rated, I don't believe, and I'm fairly certain it was about Serena getting sad that Calum like Shauna, and she ended up going to Team Flare (Lysandre) because she felt betrayed?.