It was announced during the Plus Ultra Fuji TV Anime Lineup Presentation 2018 livestream event that Shiro Yoshida’s Kabaneri of the Iron Fortress (Koutetsujou no Kabaneri) will be receiving an anime film. The film will serve as an official sequel to the 2016 television anime and will take place six months after those events.
As of this time, there was no announcement about when the movie will be completed or released in Japanese theaters; however, a promotional video was released for the film.
MyAnimeList.net describes Kabaneri of the Iron Fortress as follows:
The world is in the midst of the industrial revolution when horrific creatures emerge from a mysterious virus, ripping through the flesh of humans to sate their never-ending appetite. The only way to kill these beings, known as “Kabane,” is by destroying their steel-coated hearts. However, if bitten by one of these monsters, the victim is doomed to a fate worse than death, as the fallen rise once more to join the ranks of their fellow undead.
Only the most fortified of civilizations have survived this turmoil, as is the case with the island of Hinomoto, where mankind has created a massive wall to protect themselves from the endless hordes of Kabane. The only way into these giant fortresses is via heavily-armored trains, which are serviced and built by young men such as Ikoma. Having created a deadly weapon that he believes will easily pierce through the hearts of Kabane, Ikoma eagerly awaits the day when he will be able to fight using his new invention. Little does he know, however, that his chance will come much sooner than he expected…
A review of the 2016 anime can be found here.