A mobile gacha game published by CyberAgent. The player takes the role of the Captain and is tasked with training and advising the Alterna, schoolgirls who protect humans from hostile Night Beasts.
One of the most notable features was allowing the player to experience certain scenes with the Alterna in VR, including character and event stories, karaoke, and lying in bed with them.
The online version ended service on January 4, 2022, and was converted to an offline version the next day.
