The announcement for the OVA third season was made at the “Game no Dengeki Kanshasai 2018 featuring Dengeki Bunko” event on March 10, 2018, ten months after the release of the last fourth volume of the second season.
Because of its meaningful title, many fans expected that an announcement for the next season might happen in the event.
The anime’s director Hideyo Yamamoto said on Twitter, “It looks like the event was well received (^ ^).