Kabaneri of the Iron Fortress was a surprise original anime series hit from WIT Studio, which produces Attack on Titan and Vinland Saga, and fans had been hoping for the series to branch off with a second season. It's not a full second season, but the franchise did indeed continue with a sequel film, The Battle of Unato, taking place after the events of the first season. With a new story exploring Mumei and some new additions to the franchise exclusive to the film's story, it was a major success with fans.
To celebrate the Blu-ray and DVD release of Kabaneri of the Iron Fortress: The Battle of Unato in Japan, original character designer Haruhiko Mikimoto illustrated a gorgeous new cover. The home video release of the film is scheduled for December 11th in Japan, but fans outside of Japan can currently stream the film on Netflix.
With a completely original story taking place after the original series focusing on Mumei, Tetsuro Araki returns to direct and write Kabaneri of the Iron Fortress: The Battle of Unato. Ichiro Okouuchi (creator of Code Geass) is handling the organization, Hiroyuki Sawano (Attack on Titan) composes the music, and Haruhiko Mikimoto (Gunbuster) handles character designs. Returning voice cast members include Tasuku Hatanaka as Ikoma, Sayaka Senbongi as Mumei, Maaya Uchida as Ayame, Toshiki Masuda as Kurusu, Kanae Oki as Kajika, Mariya Ise as Yukina, Ryota Ohsaka as Sukari, and Kensuke Satou as Kibito.
As for the original series, Kabaneri of the Iron Fortress is an original anime series produced by Wit Studio, directed by Tetsuro Araki, written by Ichiro Okouchi, with music composed by Hiroyuki Sawano, and character designs by Haruhiko Minimoto. While you can find the sequel film on Netflix, you can currently only stream the series through Crunchyroll and Amazon Prime Video.
Crunchyroll describes the series as such, "At a time when the industrial revolution was carrying the world into the modern age, a horde of undead monsters suddenly appeared. They could not be killed unless their hearts, which were protected by a layer of iron, were pierced. Humans bitten by them would come back as undead monsters themselves. These undead, which would later be known as "Kabane," exploded in population until they finally overran the world. The people of Hinomoto, a nation in the far east, built fortresses known as "stations" throughout the land that have allowed them to survive the threat of the Kabane.
People can only travel between these stations using fortified steam locomotives known as 'Hayajiro,' and they have managed to stay alive by sharing resources in this way. Ikoma is a young steamsmith living at Aragane Station, a city that specializes in the manufacture of iron and steam engines. He is working on developing a unique anti-Kabane weapon called a "piercing gun" as he waits for his chance to prove his strength. Then, one day, a Hayajiro called the 'Iron Fortress' makes its way through the front lines to arrive at Aragane Station.
When Ikoma begins his usual maintenance routine, he sees a mysterious girl who is exempt from her Kabane inspection. That night, Ikoma sees the girl again and learns that her name is Mumei, but then an out-of-control Hayajiro overrun by Kabane charges into Aragane Station. The Kabane pour out of the train into Aragane Station. Ikoma races against the flow of the panicked residents, this time determined not to run away, but to defeat the Kabane with his piercing gun!"