The OVA will be based on the Narumi Seo character map story event that was featured in the smartphone game in April 2018. Seo, who has a unique memory disorder, will appear alongside other heroes of the Seo Research Laboratory in the OVA.

A 2-episode OVA for Suisei no Gargantia revealed during an announcement at AnimeJapan 2014.

For the second time, the masked storyteller returns to tell children tales and legends of horror and woe, such as the tale of a ventriloquist's dummy, a locker that grants wishes, a capsule toy machine that returns lost possessions, and a strange food called Ominie-san. Building on the foundation that was laid by the first, Yami Shibai 2 is a collection of Japanese scary stories of the unknown and the occult that are truly terrifying, narrated in a style of art that mimics kamishibai storytelling. [Written by MAL Rewrite]

Specials bundled with limited edition Blu-ray/DVD volumes of the Fate/kaleid liner Prisma Illya 2wei Herz!.