Ikoma

Ikoma (生駒, Ikoma) is the main protagonist and a young steam smith who formerly made a living in Aragane Station working with steam engines. He and his friend Takumi developed a steam weapon called "Tsuranuki Zutsu" which Ikoma believes is the best way to fully destroy a Kabane. However, during a Kabane attack on Aragane Station, he got bitten and was forced to use metal (bolted into his body) in order to control where the infection occurred. Fortunately Ikoma was fast enough for one part of his body not to be affected (his brain) and so he became Kabaneri. Boarding the Koutetsujou in hopes of arriving to Kongoukaku to investigate the Kabane.

Appearance
Ikoma is a bespectacled young man of average height and build. He has golden-brown eyes, and messy, light blonde-green hair. After being first bitten by a Kabane, his hair partially turns white, his skin takes on a pale green tint, and his eyes turn red. His glasses are missing a lens on the left frame while the lens on the right frame is tinted green.

Ikoma often wears his steam smith uniform, which is considerably torn after his first encounter with the Kabane. In order to stop the Kabane virus from spreading to his brain, he bolts and brands a shoddy harness to his body, which encompasses his right shoulder and some of his right torso. He also wears a tight collar around his neck, which helps keep the virus at bay.

Personality
Ikoma is a determined and foolhardy individual, set on making a difference in humanity's fight against the Kabane. His outstanding willpower to fight the Kabane and do the right thing often puts him in tough situations, but is also his best survival mechanism.

His greatest desire is to destroy the Kabane once and for all, which began after he witnessed the death of his beloved sister at their hands five years ago. However, he also maintains a keen sense of justice, prioritizing the lives of others before his own survival. After he survives being infected, he is elated at the fact that he could help others who are bitten as well.

Ikoma is a proud character who maintains his honor in spite of adversity, which clashes with his inherent desire to help others. It is because of this that he lives on to protect others aboard the Koutetsujou, despite the danger his existence poses for everybody.

Ikoma is also a tinkerer, born from his work with steam engines. He develops the Tsuranuki Zutsu with help from Takumi, which is the only known weapon that is able to pierce the caged heart of a Kabane in a single shot.

Aragane Station Arc
Ikoma works on his imperfect steam gun, during a trial his gun fails to penetrate a bar of metal which is almost as hard as a Kabane's heart cage.

He goes to his job as a steam smith and meets his friend and partner in developing the steam gun and researching Kabane, Takumi. Soon, Ikoma tells Takumi how the trial went and Takumi suggested adding more explosives. Shocked when he realizes he was missing a step (after Takumi pointed it out), he wants to go back home to finish the steam gun. Princess Ayame Yomogawa arrives and asks for her father's steam gun to be fixed. The chief calls Ikoma, and he is called "hero" by his workmates. The princess asks if he wanted to be a hero, he replies he just hated running away. The Koutetsujou arrives at the station early because the Kabane had invaded another station. Ikoma does his work cleaning and repairing the Koutetsujou, and collected a Kabane carotid artery and explained that it was "rare to get such a good specimen". He first saw Mumei here. A person is accused of being bitten by a Kabane and Ikoma exclaims that the man is not to be killed but he is to be put under supervision according to the law. Ikoma is beaten by the Bushi, the man is killed and Ikoma is thrown in jail.

Mumei visits Ikoma and asked him if he knew if the man was a Kabane. Ikoma explains that humanity cannot escape fear.

The Fusoujou arrives carrying Kabane, it crashes and enters the station with Kabane. As the Kabane invade the station, Ikoma escapes from his cell and goes on to finish his steam gun. He uses his blood as bait. He manages to kill a Kabane but he is bitten and the virus starts to infect his body. Ikoma strangles himself using a belt and a machine to stop the virus from reaching his brain. A part of his hair is changed from light green to white after the process to stop the virus.

Takumi, arrives in Ikoma's workshop and Ikoma explains that his weapon was a success but he was bitten by a Kabane and he didn't transform into one. They travel to meet up at the Koutetsujou. They are stopped by guards. Two Kabane appear and Mumei kills them near the Koutetsujou. Mumei asks Ikoma if he had changed his look, sniffs him and tells him that he was not normal. He is stopped by Kurusu and Mumei tells them that he was not a Kabane.

Another horde of Kabane attack the Koutetsujou. Ikoma saves some civilians from a steam pipe, he stops the pipe with one hand and is able to withstand the heat. A Kabane is able to penetrate the metal door, Ikoma fights off the Kabane with his new weapon. He kills the Kabane then realizes he exposed the inside of his robe; exposing his  heart as a  Kabane's. Kurusu shoots him and he is thrown out.

Later, the switch bar for the bridge is not working so they needed to use the manual bar to lower the bridge. The only problem is it is outside and swarming with Kabane. Ikoma fights off the Kabane, getting bitten multiple times but he didn't mind the pain. He lowers the manual bar and the Koutetsujou is able to move on.

He cries due to frustration, while Takumi throws out a hook in order to rescue him. Mumei goes to Ikoma's side and hooks his feet. He is soon given a suicide bag by Kurusu. Mumei explains that he is neither a Kabane nor a Human. Instead, he had become a Kabaneri.

Journey to Kongoukaku Arc
Ikoma attempts to leave the train, stating that he could incidentally turn everyone into Kabane, Mumei kicks him and says that he has a mind of human, while his body is that of a Kabane. While Mumei reveals her goals of arriving in Kongoukaku, Ikoma tries to interrupt, only to be beaten by Mumei once more. After having a nightmare, Ikoma suddenly wakes up to Mumei in the boiler car, who explains why she needs to get to Kongoukaku, while requesting the former to be her guardian. Ikoma protests, while Mumei mockingly kicks him across the room. He follows her to the other room, as Mumei claims that she smelled a Kabane.

While speaking with Mumei, Ikoma explains his past and his sister's death, blaming himself for not being able to save her. They are then attacked by a group of people, who are stopped by Ayame. While Mumei calmly leaves, Ikoma is left with Ayame, who attacks him with her knife, questioning his motives. Ikoma says that he has made a vow not to run away, as his purpose in life is to destroy the Kabane. Ayame backs off, asking if the group still doubts his true affiliation. After having a brief conversation with Ayame, Ikoma succumbs to his wounds due to the blood loss and hunger, pouncing on her, mindlessly attempting to bite her. However, Kurusu comes in and angrily berates him about his actions, pointing his gun at him. The conflict is soon stopped by Mumei, who says that the wave of Kabane is closing in.

As the locomotive itself is overtaken by a certain number of passengers, other steam smiths are also thrown in a room where Ikoma and Mumei resided, as civilians accused them of sympathizing with Kabane, planning to detach their car from the rest of the fortress. However, a large group of Kabane led by Wazatori attacked the locomotive, slaughtering the passengers nearby. Ikoma recalls his sister's death while watching the Wazatori murder a woman. Ikoma suggested he and Mumei exit the service hatch and chase after the Kabane.

The group went on the top of the locomotive, discussing on how they will eliminate the threat. As Mumei informed the steam smiths about the name of the cave, they concluded the time of their ambush. As Takumi gives Ikuma his gun, they fight through the small horde of Kabane infesting the top, while nearing the main threat. Mumei gradually got exhausted, prompting Ikoma to face the Wazatori alone, placing her trust in him. Ikoma is weakened due to his need of blood, pleading someone to help him in order to kill the rampaging Kabane. Ayame came out of the car, forming a contract with Ikoma by offering her blood in exchange for his protection. Ikoma ambushed the Wazatori from above, pointing his gun into the Kabane's heart, ultimately killing it. The group celebrated their win.

Ayame declared that Ikoma and Mumei will travel with the group.

Yashiro Station Arc
While on travel, engineers developed a new gun (with the help and assistance of Ikoma) based on Ikoma's piercing gun. Ikoma also made an enhanced experimental version of katana that has its durability increased (currently untested). After the Koutetsujou is blocked by a crumbled metal construction, Ikoma formed a plan with the rest of the personel on how to unblock the passage for the locomotive. However, Mumei disagreed with Ikoma's plan to use the longer way to the crane in order to avoid the Kabane.

Later on, Ikoma visited Mumei and questioned why she doesn't want to aid them. After a short argue, Ikoma warned her not to attack the Kabane nest directly. As they arrived near the crane, Ikoma noticed Mumei rushing towards the center of the nest, and chased after her. In the crane, Ikoma angrily looked at Mumei for not following the plan, and activated the machine. After a large herd started engulfing the construction, the Bushi warned Ikoma about retreating to the locomotive. Ikoma goes after Takumi and takes control over the crane himself, in order to protect the two. He noticed exhausted Mumei going towards the Kabane to fight them alone, and rushed to her after she got overpowered and kicked off the crane by a Wazatori, stopping the crane in the process.

As he carried her to the passage underground, they get crushed by crumbling rocks from the damage done to the construction.

They survive the accident, with Ikoma being able to move, and Mumei being trapped under rocks. Ikoma tried to free Mumei, although unsuccesfully. A large group of Kabane attacked the two, and Ikoma went to fight the herd in order to protect Mumei. After the rescue arrived, Ikoma and Mumei are recovered and are soon reunited with everyone at the train.

Ikoma is once again tasked to control the train crane in order to move the damaged tower, which was initially the plan, and does so succesfully now. However, the Koutetsujou is targeted by a Fused Colony, and after a failed shot, Ikoma and Kurusu went out to face the Kabane approaching the vehicle. When the Fused Colony is defeated, Ikoma saved Mumei from a fall and retrieved her back to the car.

Powers and Abilities
As a human, Ikoma is rather intelligent and thinks well on his feet. He is a proficient engineer, able to design the Tsuranuki Zutsu, and thinks quickly enough to stop the Kabane virus from spreading with scrap parts around his smithy. He also exhibits some skill with picking locks as he managed to unlock his cell while Aragane station was overrun with just one hand. When under pressure, Ikoma is shown to have high pain tolerance, as he withstands bolting his metal restraints to himself, slicing his wrists, and cauterizing his bite wound with a burning piece of wood.

Increased Strength and Heat resistance: Compared to a human as a Kabaneri, Ikoma's strength and heat resistance is greatly increased. He is able to hold and bend a scalding hot pipe with his bare hands with no indication of pain, as well as return it to its proper place effortlessly. He is also able to easily defeat Wazatori, a much more powerful variation of Kabane.

Enhanced Durability: Ikoma's body is considerably stronger and more resistant, as he was able to take a bullet to the chest and still fight multiple Kabane.

Enhanced Regeneration: His wounds evidently regenerate much more quickly, his vitality making him capable of recovering from a wound that is fatal to humans.

Immunity: After being converted into a Kabaneri, Ikoma developed immunity from Kabane bites. This is proven by him being bitten several times throughout the series without turning to a kabane.

Kabane restriction/inhibitor: Like Mumei, he wears a restraint around his neck in the form of a metal harness. It is possible that Ikoma could potentially be more powerful without his restraint as well. However, as a half-Kabane, he requires blood to unlock his full potential and risk himself into turning to Kabane without drinking any blood.

Takumi
Takumi is Ikoma's close friend. They are often seen together, and as fellow Steam Smiths, they developed a gun that is able to pierce Kabane's heart. Ikoma puts great trust in Takumi, uncovering his bite wound to him.

Mumei
Mumei is a Kabaneri turned Nue, and like Ikoma, had lost all her biological family to the Kabane. it is clear that Ikoma cares deeply for her. When Takumi questions whether Ikoma sees Mumei as a replacement of sorts for his late sister, Ikoma, shocked, claims that he does not see Mumei as a sister, and that the only thing the two share in common is maybe their short stature. Despite telling Takumi that Mumei is a "brute", a flashback reveals that he sees an innocent and kind spirit in Mumei like that of his sister[8]. This leads him to be protective of Mumei, even though she is a better fighter than he is. Biba, having recognised this kindness since he took Mumei in, deems it her only weakness (and one he is willing to overlook).

When Ikoma learned about Mumei's birth name, Hotsumi (which means heaps of rice), he decided to turn Mumei back into a human, kill all the Kabane and take back all the stations and rice paddies - just so that he can "fill her belly with rice", just like how Mumei's mother wanted to when she bestowed that name. This promise between the two soon becomes his reason for living. In Episode 11, Ikoma is broken after thinking that Mumei no longer remembers that promise, but after learning that there is a possibility of bringing her back, Ikoma shows that he is willing to die to fulfil his promise to Mumei and finally "become a man he can be proud of".

Trivia
生駒
 * Ikoma is the first person in the series to be seen turning into a Kabaneri.