First chapter of Extra Stage is officially translated. And as if to make up for Volume 1’s sausage fest of a first chapter, this chapter consists of (almost) exclusively female characters.
Unfortunately for those who have not watched the anime, this chapter is a huge spoiler. While it indeed takes place before the anime, the narration sequences reference future events rather explicitly. So if you haven’t seen the anime yet, I recommend watching it before reading.
JeruTz Translations 