Kabaneri of the Iron Fortress

The industrial revolution has brought significant advancements, but it's also led to a terrible cost: the emergence of Kabane, creatures born from a mysterious virus that feed on human flesh. Their steel-coated hearts are the only vulnerable part, and destroying them is the only way to kill these beings. On the island of Hinomoto, a massive wall protects its inhabitants from the Kabane hordes, and heavily-armored trains are the only means of entry. Ikoma, a young man responsible for servicing and building these trains, has created a deadly device he believes will pierce Kabane hearts, and he's eager to test it.