One great thing about the original Steins;Gate story was that it was a largely closed system, largely working with a well defined set of characters. The story is being continued this in novel/audio drama Steins; Gate: Heijikyokusen (Closed Curves) no Epigraphin this month, then Eigoukaigi (Eternal Recurrence) no Pandora this winter (January 25th). Today we learn that these will introduce one of rare, hitherto missing pieces in the SG loop.
The canonical story plotted by Chiyomaru Shikura and written by Masashi Takimoto (novel) and Tooru Yasumoto(audio drama) is set in the Beta timeline's year 2010.
From these stories, with illustration from designer Huke, meet Yuki Amane - this the the first canonical appearance of a cosplayer whose significance can be guessed by the sirname - or discovered with a bit of Googling. If she looks different from her card game appearence, it might be because the tomboy, who generally wears her hair in pigtails or braids, also has a thing for wigs.
Previously previewed was Japanese American university associate (senpei) of Kurisu Makise and expert in neuroscience/artificial intelligence.
Other new characters include Mayuri Shiina's relative from the year 2036 Kagari Shiina and another contemporary cosplay companions, as well as new figures from the series' academic world.
There is fan speculation that the books/audio drama will tie into the upcoming Steins;Gate anime movie.