A new PV was released yesterday.
http://youtu.be/QBCDzuXxEIc
So we got
Suwabe Junichi as Kurosu
Okamoto Nobuhuiko as Serge
Suzumura Kenichi as Haska
Tsukimiya Midori as Nyankichi
Takamori Natsumi as Yuiga
as well as pre-airing screenshots for Ep5.
http://kadokawa-anime.jp/itsu-ten/story/post-50.php
It looks like they're going to make the events in vol.4 to happen faster, then I wonder what will ep10 which has the similar title to vol.3 be like.