WMG / Kabaneri of the Iron Fortress

Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.

The Kabaneri's (the infected who retain their sapience) power comes from their bloodflow to the brain.

In the first episode, Just before decapitating a kabane, Mumei takes a ribbon off her neck, making her eyes glow just like those of the kabane, she also does this in the trailers, and everytime she fights, there is no ribbon on her neck. It would be possible that restricting the blood flow to the brain does not actually kill the virus, but it goes into a state similar to hibernation, where the infected retains their sapience, but also taps into the strength and agility of the kabane. Thus, they need some limiters outside combat, as possibly, unrestricted blood flow to the brain would allow the virus to turn the Kabaneri into a kabane.

The Kabane's virus is what caused the world's industrial revolution.

The virus that turns humans into Kabane generates a lot of heat, as evidenced by the glowing veins and heart of the Kabane. If it generates enough heat, it could be used to boil water, creating steam, and setting off the entire industrial revolution. If used on animals, it's free energy, and free iron from their blood. If it wasn't for the zombification, it would be an incredible tool to kick start any nation into modernity!

The Kabaneri are immune to further infections from the virus

Between Ikoma getting launched out of the train and when he pulls the lever, he appears to have been wounded, as he has blood all over himself. These wounds must have come from the Kabane he fought through to get there, but he doesn't get the usual symptoms of infection, like the purple flesh. This means that the virus probably like chicken pox, i.e. once you've caught it and lived, you're immune to future infection.

• Confirmed; Mumei says in Episode 3 that Kabaneri don't have to worry about being bitten.

After a long romantic arc, Ikoma will have sex with a girl and infect her.

We see that the virus is still possibly alive inside Ikoma, as it changes the color of his heart, but does not affect his brain. It's possible that when and if Ikoma gets a romantic interest (most possibly Ayame or Kajika) who he would then have intercourse with, he would infect her as the virus most likely transfers through contact with blood (like many real life STD's.) Then one of two things could happen:

• Either she also becomes a Kabaneri, possibly after being presumed dead, only to rise back up and kick ass
• Or she becomes a Kabane, and Ikoma is forced to kill her. The scene would then be regarded as one of the more unique ways to kill off a character.
• Jossed. Ikoma isn't actually involved in any romance throughout the series.

The name Kabane is a short form or twisted form of shikabane which means dead body. Kabaneri could be a combination of shikabane and kari (to hunt)

• This is supported in both the zombie-esque nature of the Kabane, and the previous translations which referred to them as corpses.

Ikoma and Mumei

Mumei is actually Ikoma's sister who has somehow survived his attempt to blow her heart up with a suicide pack when she began transforming.

• To this theory's credit, when Mumei reveals her Kabaneri nature, her glowing spot is on her back, rather than the front, but still on the left side of the upper torso, like her heart is positioned deeper than it is normally in a human body - although rare, there are cases of people born with internal organs in positions different than normal, without however inconveniencing them (see mirrored organs, for example). So, the suicide pack didn't quite work because it didn't manage to hit the heart correctly, but at the same time the shock and injury stopped the blood flow to her brain enough to avoid the takeover from the virus. Still enough, however, to make her lose her memory.

There's going to be a Love Dodecahedron.

Takumi likes Kajika, who likes Ikoma. Then there's also Kurusu, who loves Ayame, who'd (If she doesn't die in episode 4) like Ikoma. Then there's Mumei, who's the perfect wildcard in all of this. As a bonus: If Ikoma does kill Ayame come episode 4, Kurusu will heavily despise Ikoma, even more so than he does now.

• Jossed in that Ayame lives and apparently returns Kurusu's feelings.

The Kabane have a Hive Mind

Time Stamp: 4-28-16In the first three episodes of the Anime, several allusions are made to the Kabane being smarter than they look. In the first episode, the Kabane demonstrate the ability to commandeer a Hayajiro, though this could simply be luck. Later on, they are shown to both be able to wield weapons and feel anger (if Mumei's tactics are any indication). Furthermore, the Kabane seem to know that the Hayajiro are how humans move from Station to Station.

At the same time, the Kabane also demonstrate great feats of stupidity. Two Kabane arrive at the Kotetsujo and don't even bother running, and instead just mozy along. In episode three, Shino doesn't even seem to realize that there are humans are all around her. Alone, the Kabane seem... lost.

That's the critical factor though. In groups, in hordes, Kabane demonstrate emotions, physical control, and something disturbingly close to a tactical mindset. Alone, they're just zombies, and fairly poor ones at that.

Of course, there are many, many Kabane in the world, and broken clocks are right twice a day. Throw enough into the mix, and some will act like they're smart. But we also see what can be classified as a rudimentary psychic power, courtesy of Mumei. In episode three (and alluded to in the second episode) Mumei demonstrates a propensity to sense what can be called the aura of a Kabane. She knows immediately that Ikoma is neither human nor Kabane, and almost manages to locate Shino at the beginning. She doesn't do this by searching for obvious marks or vague ticks of character, she literally senses that Shino is a Kabane from a totally different train car.

Now this could be chocked up to something silly like spiritual training, but then we come to Ikoma and his dreams. Again in episodes two and three, Ikoma dreams twice, recalling the death of his sister. Specifically, he dreams that she attacks him, and that later he is bitten by a Kabane, while she begs him for help. These are not events occurred in his account of the tale to Mumei. Mumei tells Ikoma that when she uses her power for too long, she falls asleep, and what happens when someone is asleep?

Am I reading too much into this? Maybe. But if I'm right, we may see that the Kabane are much more than we think they are, and that maybe, just maybe, Ikoma's sister is still out there.

• The Kabanes that attack the train in Episode 4 seem scarily organized, like they were waiting just for one to pass and knew that the mountainous area made trains more vulnerable to attacks from above, or even that previous attacks and escapes made an higher chance that the people of the Koutetsujo chose that quicker but more dangerous path. On top of that, the episode introduces a variety of Kabane that is much more strong and intelligent than the regular ones, and who seems to act like an effective leader.
• Confirmed with the introduction of Black Smoke in Episode 5.

The silhouette we see in the end of the opening:

• Is a Kabane that has become smart enough to regain their humanity.
• Is Ikoma's sister, grown up
• Is Mumei's brother.
  • Very strongly implied to be true in Episode 6 and confirmed in Episode 7. He's Biba The Liberator, the Shogun's son and the leader of the Hunters, the elite Kabane extermination unit.
• Is "patient zero" of the kabane virus.

Kurusu is Kabaneri

He doesn't know it yet though. Mumei seems intrigued when he doesn't flinch at the bullet she threw at him at top speed and comes off with just a scratch after deflecting her bullet. With reflexes fast enough to rival hers.

• That would possibly explain how being stabbed through by a katana (half of the blade came out from his back!) seems to not have inconvenienced him that much. It wouldn't explain, however, how he sates the lust for blood, and we also don't know if a Kabaneri can drink the blood of another Kabaneri. Unless Kurusu knows, loathes himself for having become "impure" (also explaining his strong hostility towards Mumei and Ikoma), and has some secret source of blood (a loyal friend?).

The Kabane are the ancestral form of the Yoma or at least a related species

The Kabane result in Kabeneri, hybrids with superior physical prowess and combat ability. The Organization might have isolated the Kabane virus or parasite to create the Yoma. Like the Kabane, the Yoma are effectively a parasite that takes over the body of its host. In the case of the Yoma, the host's own thought processes are subverted by a malignant intelligence. So long as the host retains their humanity, they become excellent super soldiers. However the Yoma are far better adapted than the Kabane, being an ambush predator with a lower chance of depleting their food supply and the Warriors are easier to mass produce than the Kabaneri with a Healing Factor and other powers thrown in beyond the physical enhancements.

Kabaneri who turn become the hearts of fused colonies.

Mumei's friend in Episode 6 got executed even before showing the Volcanic Veins that characterise the Kabane. This implies that the threat posed by a Kabaneri fully turning is sufficient to warrent immediate execution.

• It might be true. In episode 9 Biba turns Horobi into the heart of a fused colony.
• Partially confirmed: it requires a Black Blood injection, though.

Mumei's Brother is also a Kabaneri.

And he is planning on wedding Mumei in an Adam and Eve Plot intended to breed a race of Kabaneri Ubermensch.

• Confirmed in episode 12. Although the above is Jossed in that he only needed Mumei to turn her into a Fused Colony to destroy Kongokaku city, and intended to dispose of her after the job was complete.

If Ikoma survives to the end of the series, he will become a truly heroic version of Biba.

Bonus points if the final scene is him saving a little girl and her mother, and swearing to protect the weak.

• Jossed. The series ended on a sequel hook, with Ikoma barely surviving only thanks to Biba himself without doing anything truly heroic.

Kabane and Kabaneri have the ability to regrow lost limbs

When Ikoma loses his arm to a bullet, the stump ends above the elbow. When we see him next, it ends below the elbow, and in the ending of the 12th episode, his arm is even longer than before.

• Supported by the fact that all Kabane shown in the anime have all of their limbs, even though at least some of them would have lost some in the past, due to injury or close encounters with Hayajiro.
• But also subtly adverted in The Battle of Unato, where Ikoma's new arm is revealed to be some sort of mechanical prosthetic.

Wazatori can also be the result of Kabaneri that have not had blood and fully turned

Mumei reveals that if she doesn't get blood, she will eventually turn into a Kabane. The few Wazatori shown not only know proper stances of their required fighting disciplines, but also have the correct gear. It is unlikely that they would also know how to scavenge and equip such articles, so they might be the remnants of their former lives as Kabaneri. As for how can they be so prolific? Ikoma might not be the only one to have figured out how to stop the infection, but he is the only one who did it on his own and was then told he needed blood; the others must have fallen victim to their own thirst before realizing, turning into Wazatori.

Biba's "Noble Demon" is actually another "Bastard Backstab"

It's basically confirmed in every way but visually that Biba doses Ikoma with the white-blood during the final duel, in order to undo Ikoma's advanced Kabane state. The last possible chance for Biba to do so would be when Ikoma goes blind. Biba goes for the back-stab where Ikoma promptly denies him and blows his arm off, but not before Biba quickly pulls the syringe and doses Ikoma.

It is arguable that during the duel Biba felt he couldn't defeat Ikoma in his current state, and decided to use the white-blood to even the odds in his favor.

• Supported by Biba Crazy-Prepared trope, his general character traits throughout the series, and the fact that Biba eventaully gets back up and starts shooting at Ikoma after he's rendered unconscious from exhaustion.
• With this in mind, is is possible Biba's line "You found the coward within me" was more about his dishonor in using the white-blood, rather than the back-stab itself.