It has been announced that the Kabaneri of the Iron Fortress: The Battle of Unato (Kōtetsujō no Kabaneri: Unato Kessen) sequel anime film will open in Japan in Spring 2019. The film will focus on the character of Mumei.
The film will take place half a year after the story of the original television anime series. The official website for the anime lists the film as the “middle volume.”
The Kabaneri of the Iron Fortress anime aired on Japanese television from April-July 2016. The series has also received two compilation films that premiered in December 2016 and January 2017 in Japan.