
Quick answer — Shinobu Matsumoto voices You Mishimagi in Softenni, Ryousuke Endou in SHIROBAKO, Fujio Mine in Ace of the Diamond and 13 more characters.
Shinobu Matsumoto voices You Mishimagi (Softenni), Ryousuke Endou (SHIROBAKO), Fujio Mine (Ace of the Diamond), Ihlen Schwarzkopf (Saga of Tanya the Evil), Ryouma Shinjou (The Yakuza's Guide to Babysitting), Senshi (No Game, No Life), Gusta Raizeo (The Misfit of Demon King Academy: History’s Strongest Demon King Reincarnates and Goes to School with His Descendants), Mini Taichou (Train to the End of the World) and 8 more.
You Mishimagi is voiced in Japanese by Shinobu Matsumoto.