Ikoma (生駒, Ikoma) is the main protagonist of Kabanari of the Iron Fortress, Originally, a young steamsmith 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 onto his body) in order to control where the infection occurred. Fortunately, Ikoma was fast enough for his brain to resist the infection, transforming himself into a Kabaneri.
Upon boarding the Koutetsujou, Ikoma met a mysterious girl named Mumei, whom later revealed herself to be a Kabanari like him, Initially the pair became subject to suspension by the passengers. However after defeating the threat of a Wazatori, Ikoma and Mumei eventually proved their allegiance towards Princess Ayame Yomogawa and began their journey towards Kongoukaku in the hope of investigating the Kabane.
Ikoma is a bespectacled young man of average height and build. He has golden-brown eyes, and messy, light blonde-green hair. After being 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 steamsmith's uniform, (which is considerably torn after his first encounter with the Kabane), he primarily dons a worn-out crimson cape. 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.
After he losts his arm, he use his Tsuranuki Zutsu such as a prothesis, cuts his green hair and leaves behind his glasses.
PersonalityEditIkoma is portrayed as a noble-hearted, headstrong, ambitious, tenacious and foolhardy individual armed with a committed resolve matched with sheer determination and willpower.
Rational and level-headed, Ikoma is noticeably calm under pressure as he maintains a steadfast and resolute approach towards tackling problems which acts as his best survival mechanism. Despite this however, Ikoma can at times act considerably rash, stubborn and Impulsive which often unitentionally places him into perilous and even fatal situations which several people have warned him about.
Ikoma maintains a keen sense of justice prioritising the lives of other before his own, and he also bears a strong sense of honour in spite of adversity which clashes with his inherent desire to help others, Ikoma’s valoress nature has led him to be inspired by several, most notably Takumi, Kajika and has even earned him the respect of Princess Ayame but has also received mild cynicism from others mostl especially Kurusu.
The outbreak of the Kabane outbreak coupled with Hatsune’s death greatly affected Ikoma leaving him emotionally traumatised and remorseful over, factors which heavily attributed towards his burning desire to be-rid the Kabane from existence, henceforth, Ikoma dedicated his existence towards achieving this goal. This tragic experience moulded Ikoma to adopt a brave-hearted demeanour and is generally fearless in the face of peril and even death.
Hatsune's memory serves as his moral code and reminder for him to never flee from a situation from which he can help and thus Ikoma displays a great level of loyalty, courageousness and selflessness, this nature ultimately serves as a purpose to redeem Ikoma for his inability to save Hatsune and to become a person whom he can become proud of.
As a tinkerer, born from his work with steam engines, Ikoma is noticeably pragmatic, resourceful and intuitive, on top his creation of 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.
Ikoma was born in Hinomoto, where he grew up alongside his loving sister Hatsune. One day, the sibling found a pair of blue rocks located near a lake, Ikoma initially offered his sister to have both of them, however, Hatsune insisted that they both kept one each as ‘good luck charms’. (No knowledge is given regarding the fate or whereabouts of their parents, other than Ikoma noted that he 'lost his family a long time ago', it is assumed that they most presumably perished to the Kabane outbreak.)
Around the age of 12, the station Ikoma and Hatsune resided in became overrun by the Kabane which resulted in all the adults fleeing in fear, where tragically through the devastation his sister was caught by the Kabane. Powerless to do anything, Ikoma fled and desperately sought for aid from terrified citizens only to be pushed aside. By the time Ikoma returned, he discovered that Hatsune had been killed by the Kabane and had already begun to reanimate, Ikoma tearfully weeped over her corpse and apologized for his cowardliness before using a suicide bag in order to prevent her from attacking him. Emotionally traumatised after this event, Ikoma developed a deep hatred for the Kabane, and thus he strived to discover a way to fight back against them in order to avenge Hatsune’s death and to ultimately redeem himself for his inability to protect her. 
At some point, later, Ikoma journeyed to Aragane Station, where he settled into the fortified community, under the rule of Lord Kenshou Yomogawa, upon where he developed a strong dislike for the Bushi for their ruthless and oppressive methods. Ikoma managed to gain employment as a Steam Smith where he helped to repair and maintain several Hayajiro, where he befriended several other steam smiths including Takumi, whom became his closest friend, alongside Kajika. Throughout the following years, Ikoma began extensively researching into Kabane biology (additionally he collected several samples.) He worked alongside Takumi (Utilising materials and equipment from his smithy) in developing and constructing a specialised weapon named the ‘Tsuranuki Zutsu’ designed specifically to pierce directly through a Kabane’s heart cage. 
Ikoma works on his unperfected 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 steamsmith and meets his friend and partner involved into 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 asks 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 (possibly due to the stress caused to his body by this event).
Takumi, arrives at 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 which shows his heart as that of 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 that it is outside and swarming with Kabane. Ikoma fights off the Kabane, getting bitten multiple times without minding 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, he chooses to ignore it. Mumei jumps off the Koutetsujou towards Ikoma's side and hooks up 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.
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 all 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 steamsmiths are also thrown into a room where Ikoma and Mumei are in, 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 suggests he and Mumei exit the service hatch and chase after the Kabane.
The group went onto the top of the locomotive, discussing on how they will eliminate the threat. As Mumei informed the steamsmiths 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 for 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 at 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 ArcEdit
While en route, 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 personnel 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 argument, 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 an 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 incident, 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 off to fight the herd in order to protect Mumei. After rescue arrived, Ikoma and Mumei are recovered and soon reunited with everyone at the train.
Ikoma is once again tasked to control the crane in order to move the damaged tower, which was the initial plan, and succeeds. 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 saves Mumei from a fall and retrieves her back to the car.
Powers and AbilitiesEdit
As a Steam Smith, Ikoma has been educated in repairing steam engines and thus is proficient in the field of mechanics and engineering. Ikoma has proven to be a talented inventor, on top of him being able to personally handcraft and construct his own specialised weapon the 'Tsuranuki Zutsu', a weaponised rivet gun which is specifically designed to pierce directly through a Kabane’s heart cage. This becomes one of the few known weapons throughout Hinomoto fully capable of killing a Kabane with a single shot.
A tinkerer by nature, Ikoma has proven to be incredibly intuitive and resourceful, as demonstrated after his encounter with a Kabane, (despite becoming bitten), he was able to quickly redirect and prevent the virus from spreading around his body by utilizing various pieces of equipment located around his smithy. Ikoma has also exhibited reasonable knowledge of lockpicking. Whenever under pressure, Ikoma has demonstrated to posses a high pain tolerance as proven through slicing his wrist, cauterizing his bite wound (with a burning piece of wood), alongside enduring several bolted metal restraits attacthed to his body.
Originally, Ikoma had form of physical training and thus was a rather fallible combatant, after receiving several fighting techniques from Mumei (whom is an exceptionally skilled hand-to-hand combatant), Ikoma gradually grows into a capable fighter and is able to engage and hold his ground against several opponents with noteworthy skill, sparring against the likes of the trained Bushi and even Hunters. However, Ikoma’s combat skills could be considered average and he can still become overpowered by highly skilled combatants including Kurusu and Biba.
Upon Ikoma’s successful testing of the Tsuranuki Zutsu' on a stray Kabane, he is unfortunately bitten in the process and becomes infected. Acting upon survival instinct, Ikoma was able to utilize several tools and pieces of equipment to redirect the infection from spreading throughout his body and prevent it from reaching his brain, essentially (yet unknowingly) transforming himself into a Kabaneri - a hybrid race between that of a human and the Kabane.
Increased Strength and Heat resistance: Compared to a human, as a Kabaneri Ikoma's strength and heat resistance are 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 a 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 turned into a Kabaneri, Ikoma develops immunity from Kabane bites. This is proven by him being bitten several times throughout the series without turning into 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 risks himself into turning to a Kabane without drinking any blood.
Takumi is Ikoma's closest friend. They are often seen together, and as fellow steamsmiths, they developed a gun that is able to pierce a Kabane's heart. Ikoma puts great trust in Takumi, uncovering his bite wound to him.
Mumei is a Kabaneri turned Nue, and like Ikoma, had lost all of 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 his 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. This leads him to be protective of Mumei, even though she is a better fighter than he is. Biba, having recognized this kindness since he took Mumei in, deems it her only weakness (one he willingly overlooks).
When Ikoma learned about Mumei's birth name, Hozumi (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 her 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 fulfill his promise to Mumei and finally "become a man he can be proud of".
- The name "Ikoma" consists of "生", meaning "life", "existence" or "birth" and "馬" for horse.
- Ikoma is the first person in the series to be seen turning into a Kabaneri.
- Ikoma keeps a blue pebble as a personal memento of his sister Hatsune, the significance of the pebble is to act as a ‘good luck charm’, for Ikoma. Interestingly several incidents prove to merit its value most notably when it aided Ikoma during his transformation into a Kabanari as well as his battle against Biba.
- Through a conversion with Mumei, It is hinted that Ikoma may have contemplated suicide after Hatsune’s death.