Kabaneri of the Iron Fortress Season 1 Episode 4 Flowing Blood ( Air Date 2016-05-06 ) Genre Animation, Drama, Action & Adventure, Sci-Fi & Fantasy category. Overview "The other people lock Ikoma and Mumei into the rear car. But that means the Kotetsujyo has lost two of their best fighters. Just then, the Kabane attack. What's more, among them is a Wazatori, a Kabane that has the ability to learn and become stronger with each battle...".