Given: Uragawa no Sonzai
CrunchyrollAka: Given: Uragawa no Sonzai • Given: Can't Say Goodbye, I'm Still Drifting With Your Echoes. • ギヴン うらがわの存在
Synonyms: Given OVA • Given OAD
The OVA, bundled with the special edition version of the seventh manga volume, will tell an "other side" story centered on Mafuyu Satou and Ritsuka Uenoyama that wasn't featured in the Given movie.
(Source: MAL News)
