Katana Man

Samurai Sword (サムライソード) is a human-devil hybrid who merged with the Katana Devil (刀の). His grandfather was the Mob Boss killed by Denji and because of that he teamed up with Akane to get revenge on Denji and steal his heart.

He is the primary antagonist of the Katana Man arc and a minor antagonist in the Control Devil arc.

Human Form
Samurai Sword is a tall man with a short black hair and notable sideburns. He normally dresses in a large leather coat with a gakuran underneath.

Hybrid Form
When he transforms, he grows large swords from each of his arms and his face takes on a demonic appearance with dark skinless flesh and oversized jaw devoid of lips. His chin becomes pointed and another sword grows from his forehead where his eyes would be, with the handle sticking out of the back of his head.

Personality
Samurai Sword is selfish and cruel. He only cares about killing Denji and forcing him to apologize for killing Samurai Sword's grandfather. He will sacrifice innocent people and even his own comrades to do so, being willing to cut through them just to get to Denji. He has shown a complete disbelief in Denji's excuse that he killed his grandfather because he was a zombie, and accused Denji of being a liar.

He loves his grandfather despite knowing he was a Yakuza boss because he viewed his grandfather as a man of principles who had only killed a handful of women and children.

Despite having his physical heart replaced with the Katana Devil, Samurai Sword considers himself to still have a human conscience and states that he doesn't sleep well on nights where he killed a zombie, in contrast to Denji who has no guilt at all.

History
At some point he had an arrangement with Akane Sawatari where his heart was replaced with the Katana Devil by her, allowing him to transform into a hybrid.

Katana Man arc
Samurai Sword ate at the same restaurant as Denji, Aki, Himeno and Power. He commented that the food was disgusting and went into a speech about refined taste and how a person's upbringing will affect them. As the others considered leaving instead of responding to him, he brought up his grandfather and showed Denji a picture of the Yakuza boss that Denji worked for in the past. Before Denji could react Samurai Sword pulled out a pistol and gunned down Denji, Himeno and Aki. Power swiftly moved out of his sight and hit him with an uppercut to knock him back. Aki summoned the Fox Devil in that opening which swallowed Samurai Sword, however Samurai Sword swiftly cut himself free after transforming.

Aki draws out a spike with a sword hilt and engages Samurai Sword. Samurai Sword is stabbed three times in a row by Aki which summons the Curse Devil. The Curse Devil grabs Samurai Sword and violently kills him. Akane Sawatari appears in the ruined building and crouches down near Samurai Sword, reviving him. As Aki watches in shock Samurai Sword dashes forwards and slashes Aki.

Before Samurai Sword can finish off Aki, Himeno intervenes by using the full power of her Ghost Devil to overwhelm him. Unable to effectively fight back, Samurai Sword begs Akane for assistance and she uses her Snake Devil to swallow the Ghost Devil while Himeno's body vanishes. In her final moments Himeno pulls Denji's chainsaw cord to revive him. Samurai Sword and Denji charge at each other as Samurai Sword swears he'll put Denji down a second time.

Samurai Sword and Denji clash multiple times, destroying the building around them. Samurai Sword's subordinates arrive to back him up and he tells them to aim for Denji's arms or his heart. Denji takes one of them hostage but Samurai Sword uses his dashing technique again to blitz Denji at high speed and cut through both Denji and the hostage. With Denji bisected and defeated, Samurai Sword's transformation became undone and he reverts to his human form while declaring victory over the Devil Hunters who can't stand up to the power of guns.

Samurai Sword and Akane lead their people outside to a van that they're trying to load Denji into, but suddenly his subordinates start dying around him.

Akane tells him that they should escape while they still can, and that it is likely that Makima herself is attacking. Cursing, Samurai Sword tries to pick up Denji but notices Kobeni approaching them. Akane tries attacking her with the Snake Devil but Kobeni nimbly avoids the attack and runs across its body towards them. He tries gunning her down but Kobeni cuts off his arm and catches his gun, shooting him twice in the back. When Kobeni runs out of bullets Akane escapes after throwing Samurai Sword's body inside the van.

Kishibe tells Denji and Power that their first mission of real combat will be to capture Samurai Sword and his accomplice Akane. At his hideout Samurai Sword is fuming over Denji and tells his underlings that he won't run away, just like how his grandfather wouldn't. Akane tells their subordinates not to worry about their boss since even if he dies he will be revived.

Akane tells Samurai Sword that they'll kill as many devil hunters as possible and try to steal Denji's heart if possible before escaping through the Snake Devil. Samurai Sword swears he'll kill Denji, while Akane tells him not to lose his cool.

During the raid on Samurai Sword's hideout, Denji took the elevator by himself after Power disembarked to fight some zombies and he encountered Samurai Sword with a couple of his subordinates. Instead of fighting right away Samurai Sword offered depending on Denji's attitude. He demanded that Denji allow himself to be killed without resistance in order to satisfy the Yakuza's anger, but Denji refused leading to both of them transforming at the same time. Samurai Sword charged at Denji, sending both of them flying through the wall and they clash in the air outside.

Denji lands on a train, followed by Samurai Sword who knocks him through the roof of the carriage and into the train. Samurai Sword blitzes Denji twice in quick succession while Denji tries to protect a civilian, leading to both of Denji's arms being cut off. Samurai Sword demands once more than he apologize for killing his grandfather but Denji claims he can still fight because he has the chainsaw on his head. Samurai Sword, baited by Denji's words, charges at him a third time and shatters the chainsaw on Denji's head while simultaneously being cut in half by a new chainsaw that Denji sprouted from his legs. Denji calls him a moron while Samurai Sword falls apart.

After recovering, Denji pulls the arm out of Samurai Sword triggering his regeneration causing his body parts to stick back together and for him to revert back to his human form. He is then tied up with a chainsaw chain and stripped to his boxers while Denji waits for Aki to arrive. Denji thinks of some way to get payback against Samurai Sword for shooting Himeno, and as Aki arrives he announces that he will hold a tournment; whichever ones of them gets the biggest scream of pain from kicking him in the nuts wins. Aki is initially reluctant but changes his mind after looking at Himeno's cigarrete which has "Easy revenge!" written on it. The two then take turns kicking him as as their way of paying respect to Himeno.

Bomb Girl arc
Denji recalled Samurai Sword's method of dashing forwards at high speed and starting thinking about how he could apply his own powers towards mobility as a result.

Control Devil arc
Samurai Sword is part of the squad assembled by Makima to kill the Chainsaw Man. While under Makima's control, he behaves protectively and with great affection towards her.

After Makima commanded her agents to attack. Samurai Sword along with other hybrids pulled out their weapon, transforming themselves into their hybrid forms, and lunged at Denji. As each makes contact with him, they are blown back by the force of him leaping forward. After Denji defeats Quanxi, Samurai Sword appears behind him, attempting to slice through Denji. He is unsuccesful, however, as it is shown Denji was able to decapitate him without taking any damage himself.

Samurai Sword is also present during final confrontation of Makima and the Chainsaw Man. While the Chainsaw Man is pulling the chunk of ground in front of him and throwing it towards Makima, who only sighs as it flies towards her. Samurai Sword and the Longsword Hybrid leap into the air together, both slicing the chunk of land and cutting it down into several dozen smaller chunks. The two, now vulnerable in the air watch as Denji appears from behind the debris, falling down towards them before cutting them both with his chainsaws.

Hybrid Powers

 * Hybrid Transformation: By removing his left hand from his body and revealing a katana which emerges from the stump, he can transform into his Samurai Sword form with katanas emerging from his arms and his head. Removing the katana from his arm will undo his transformation. After his transformation is undone he is unable to fight for a while.
 * Augmented Strength: Samurai Sword's strength is greatly enhanced in his transformed state, allowing him to cut through solid walls with his slashes. He is also strong enough to cut the Fox Devil's flesh and the reinforced uniform used by public safety members, however he was not capable of making a deep cut in the suit with just one slash.
 * Augmented Durability: In his hybrid form, Samurai Sword is durable enough to survive getting thrown through walls and falling from buildings without taking any damage. He also managed to survive being swallowed by the Fox Devil.
 * Augmented Speed: After transforming, Samurai Sword's speed is improved, allowing him to compete with Aki and Denji in terms of speed. He can also slash walls in the blink of an eye.
 * Sword-Draw Dash: Samurai Sword's special technique, it is a quick-draw sword technique (also known as iajitsu). By crouching down low and preparing to unleash his swords, Samurai Sword can dash forward at incredible speeds and slash at his opponent as he goes by them, often appearing to simply teleport past them before his attacks appear on his opponents body. Samurai Sword moves faster than the average human eye can see and he can use this technique multiple times in a row without any apparent drawback. While this attack tends to only affect a specific part of the enemy's body, it does so with significant force, severing limbs or cutting the opponent in half. However Samurai Sword does not actually disappear when he uses this attack, meaning it is possible to block or counterattack this move and wound him. If he gets injured while using this technique, the damage will take a few moments before it appears on his body, just like when he cuts someone with this attack.


 * Blood Consumption: As a hybrid, Samurai Sword is able to restore his health by consuming blood. After being bifurcated by Denji, he was able to regenerate his body.
 * Nigh-Immortality: Due to being a hybrid, Samurai Sword is immortal and nearly unkillable. He can survive being bifurcated, getting shot and take all kinds of injuries that would kill most devils. Even if he dies, as long as someone removes his left hand, Samurai Sword can come back to life in perfect condition. After being killed by the Curse Devil, Akane managed to revive him, despite the curse being believed to be lethal.

Skillset

 * Marksmanship: In his human form Samurai Sword has used a handgun to gun down Denji, Aki and Himeno at close range.
 * Swordsmanship: Samurai Sword is a skilled fighter with his arm blades, able to clash against Aki and Denji and ultimately overwhelm them with his powerful slashes.

Weaknesses

 * Cooldown Period: Once his transformation is undone Samurai Sword is unable to enter his hybrid form again for a certain period of time. This weakness is unique to him, since Denji is capable of going in and out of his hybrid form as long as he has enough blood.

Trivia

 * When Samurai Sword uses his Sword-Draw Dash attack, his position mimics a swordsman reaching for the blade at their waist, with the left hand acting as the katana and the right hand moving in a position to draw it.