School days? I remember that there was a bloodbath at the end. But I don't remember why... In the russian version cut out all the sex scenes but left the blood.
Tags edited to include parody and catherine (game). The picture's title on Pixiv is ã‚ャサ☆リン = Cathe☆rine. This is a reference to the scene where Vincent wakes up with Catherine in his bed and Katherine walks in on them. The fact that Konata is wearing boxers similar to Vincent's also implies to this reference, too.