Kabaneri of the Iron Fortress

At Aragane Station, Ikoma, a young steamsmith, confronts a Kabane attack using his newly developed Piercing gun. Amid the chaos, he battles both the monstrous threat and his own personal demons.

Ikoma survives and makes his way toward the final Hayajiro at Kenkin Station, the Kotetsujyo. Ayame and her group are left to face the Kabane, but a mysterious girl named Mumei arrives and fights her way through the horde, clearing a path to the Kotetsujyo with remarkable skill.

Escaping Kenkin Station, the Kotetsujyo makes its way toward Kongokaku, a fortress of the Shogunate. Tensions rise aboard the train as passengers turn against Ikoma and Mumei, trying to force them off. Ayame, thrust into a leadership role, struggles to maintain control and quell the unrest.

Ikoma and Mumei are trapped in the rear car by their companions, leaving the Kotetsujō at a disadvantage with two of its strongest members missing. As the group faces a Kabane attack, they discover that one of the attackers is a Wazatori, a rare Kabane that grows stronger through combat.

The Kotetsujyo rescues survivors from the destroyed Yatsushiro Station, including Enoku, a former acquaintance of Mumei. His harsh words about her growing attachment to the Kotetsujyo and loss of strength shake her confidence, leading her to act impulsively in battle and place herself in peril.

The Kotetsujyo confronts a massive horde of Kabane known as the Black Smoke, facing seemingly insurmountable odds. At the same time, Ikoma and Mumei are trapped in an abandoned subway station, overwhelmed by Kabane and physical debris, with no reinforcements available. Despite the dire circumstances, Ikoma remains resolute and ready to fight.

The Kotetsujō arrives at Shitori Station, the first inhabited station they have encountered since departing Kenkin Station. While Ikoma and the others venture out to gather supplies and enjoy a rare moment of calm, Ayame attempts to negotiate for food, facing the challenge of scarce resources.

Biba Tenshin, the leader of the Hunter division responsible for eliminating Kabane, is the older brother that Mumei serves. While many regard Biba as a heroic figure, Ikoma harbors deep distrust toward him, believing it was Biba who transformed Mumei into a Kabaneri.

The Shogunate blocks access to Kongokaku due to concerns over Biba's growing influence. After securing a meeting, Biba kills the Lord of Iwado Station, marking the start of his campaign to overthrow the ruling power.

Takumi and his companions are held under the control of the Hunters, who require their blood, as the Kotetsujō is connected to the Kokujō. Amid growing despair, Ikoma begins planning a resistance. His goal is to reclaim freedom, dignity, and Mumei.

Biba is reunited with his father, Shogun Koukyo, after a decade apart, while Mumei prepares with his Nue in the background. Ikoma, now lacking confidence and willpower, has become a shadow of his former self and can only fearfully observe the Kabane.

Kongokaku is overwhelmed by Biba's strategy, Mumei's transformation into a Nue, and a surge of Kabane. Ikoma arrives, having further modified his body, and enters the facility to rescue Mumei, aware of the risks involved.