Kurogumi Party was a live-event featuring the Akuma no Riddle voice actresses. The event had each VA singing their ending song, Uchida Maaya performing the theme song, as well as various comedic panels mostly improvised by the VAs, with Tokaku’s VA hosting the event.
Voice Actresses:
Pictures of the events:
Sumireko looks so proud of her wife 
Nio holding a massage item 
Tokaku vs Chitaru 
Isuke about to poison Shiena 
Tokaku vs Shiena 
Chitaru vs Otoya (with bunny ears) 
Tokaku vs Chitaru 
“Hitsugi, I won’t die. Because I won’t die, I will continue to love you” 
Shiena is happy to have screentime 
Suwa (Tokaku VA): Kenmochi Shiena!… I don’t remember seeing you fought. Yuki (Shiena VA): I don’t remember seeing you fought as well… Suwa: Strange… We should’ve fight. Yuki: Because i’m hiding.
The VAs performing their ED songs:
Pictures from the VAs:
“I played with Kouko-chan’s hair like in the 4th DVD cover!” 
“Takechi, s-s-stop it!! (You’re going to cut my pigtail!)” 
Promotional arts and pamphlets:
Funnies:
What’s so funny Suzu? 
Sumireko facing Tokaku 
Hitsugi about to gun Shiena’s ass 
Hitsugi caught her gf with Otoya 
Official Arts:
Fan Arts:
Watch Kurogumi Party:
https://www.bilibili.com/video/av1851754/ (recording with Chinese sub)
https://drive.google.com/file/d/0B5jaiJcqtC2-N180djROd3U0VFE/view?usp=sharing (Download the recording)
https://www.dropbox.com/s/3z3zjwqn3sqx8kb/%5Btriple0%26ihoshiku%5D%20Kurogumi%20Party.ass?dl=0 (to download the English sub in .ass file)
Sources:
http://www.koepota.jp/news/2014/09/19/0204.html
https://news.mynavi.jp/article/20140925-riddle/
https://riokichisnow.tumblr.com/post/95635028159/minor-translations-on-twitter-about-the-afternoon https://triplezeroandapockerface.tumblr.com/post/95622382007/live-reports-of-the-afternoon-show
https://twitter.com/Suwa_Ayaka/status/503885445394989057 https://twitter.com/yamada_yuki57/status/503877610204446720 https://twitter.com/Miho_Aaaa/status/503795515377451008
Akuma no Riddle CPR 