Gyutaro/Synopsis

Human Life
Gyutaro was born into poverty within the lowest class of the Entertainment District. His mother would often beat and try to kill him even before he was born due to presumed attempted miscarriage since she could not afford to feed him, but her efforts were proven to be in vain when she died of syphilis.

Throughout his childhood, he was berated for his appearance, voice, and poor hygiene by the other residents of the district. Without money and food, he was forced to eat insects and mice, which he killed with his only toy, a customer's forgotten sickle. When his sister, Ume, was born, he gained a sense of pride and acted as her "collector" within the district.

After Daki turned thirteen, he returned home from work one day, only to discover his sister tied up, burned to near-death, and left to die in a ditch because she blinded a samurai with a hairpin. He jumped into the ditch and began to panic, tearfully demanding that his sister be turned back to normal while cradling her body, threatening to kill the gods while he did so. While embracing his dying sister, the same samurai whom she blinded appeared, snuck up behind Gyutaro, and slashed his back in an attempt to kill him. He then overheard the samurai speaking to a brothel manager (Ume's madam), revealed to be the one who asked to have Gyutaro killed. However, before the samurai could kill them, Gyutaro managed to jump out of the ditch and kill the manager by stabbing her in the face with his sickle, after which he sarcastically complimented the samurai for having such a lavish lifestyle. As the samurai assumed a stance and prepared to kill him, Gyutaro mocked him for "whining and moaning about a lousy eyeball" and proceeded to split his face in half.

Despite being injured, Gyutaro carried his sister Ume's dying body throughout the Hanamachi district in search of help, but was ultimately hit with the hard and cruel truth that there was simply no one who would give aid to them, no matter where he went; they were constantly ignored by others and denied any mercy by anyone. He eventually succumbed to exhaustion, both he and Ume being on the verge of death. On the verge of death, they were found by the Upper Rank Six at the time, Doma, who was searching the Entertainment District to devour the young women of the area. He then offered to "help" them by turning them into demons, due to him being a "Nice Guy" and gave them a few drops of his blood to initiate their transformations. He then gleefully challenged them to become powerful enough to be chosen by Muzan and join the Twelve Kizuki themselves.

Demon Life
As a demon he and his sister, now known as "Daki", continued to reside in the Entertainment District and continued to terrorize and feast on its inhabitants, with the siblings seemingly developing a taste of only eating from the district's finest and most beautiful geisha and oiran of the district. After an unknown number of years, the siblings were eventually noticed and acknowledged by "that man" and given the rank of Upper Rank Six of the Twelve Kizuki. However, Muzan himself recognized that Gyutaro was the more powerful of the siblings, and acknowledged only him as the true holder.

Somewhere along his long life as a demon, Gyutaro successfully killed and ate at least fifteen Hashira of the Demon Slayer Corps while his sister killed and ate seven.

Entertainment District Arc
After a tantrum-throwing Daki called out for him, Gyutaro emerged from her body, quickly taking her to another part of the room. He reattached her severed head, comforting her while doing so. Tengen attacked the pair, but Gyutaro quickly countered it, injuring the Hashira. He then complimented the Demon Slayer on stopping his attack.

The mysterious demon further complimented Tengen's face, skin, flesh, and height, as well as his presumed popularity with women. Feeling envious of the Hashira, Gyutaro threatened him with a painful death. Hearing Daki's complaints about Nezuko Kamado's involvement, he promised to exact vengeance upon all those who had hurt her. Throwing his sickle-like weapons with great force, which returned to him shortly afterwards, Gyutaro was unable to injure Tengen or the bystanders he was protecting. He restated his envy of the Hashira, which only increased when the Demon Slayer revealed he had three wives. The mysterious demon unleashed his Blood Demon Art: Flying Blood Sickles, a barrage of blood blades. His attack accomplished nothing, as Tengen escaped through a hole he made in the floor, which surprised the emaciated demon. Gyutaro commanded his attack to turn, revealing its auto-tracking nature. Tengen deflected the attack again, throwing and then detonating several small bombs in Gyutaro's vicinity. Wrapped in his sister's sash, Gyutaro withstood the blast, smugly stating they are one.

The emaciated demon informed his opponent he was different from the previous Hashira he had fought, once again expressing his envy at Tengen's talents. He remained silent as the Sound Hashira rejected his claims, who cited Gyomei Himejima and Muichiro Tokito as examples of amazing talent, but countered by demanding to know how his Flying Blood Sickle's poison hadn't killed the Demon Slayer yet. Moments later, Gyutaro grinned, declaring Tengen's statement of poison resistance to be a bluff, and blocked the Hashira's twins blades with his dual sickles. Clashing briefly with his opponent, Gyutaro was furious at Tengen kicking his sister. He was then surprised as Tengen threw more bombs at him and his sister, which he managed to escape unscathed. He quickly deduced the true nature of the bombs, special gunpowder capable of hurting demons, leaving him confident in their eventual victory, but was surprised as Tengen's subsequent sword strike extended. Marveling at the Hashira's grip strength, Gyutaro deflected the attack, but was left with a slight wound to his neck. He warned Tengen of his impending death, only to be surprised by the arrival of Inosuke Hashibira and Zenitsu Agatsuma.

The mysterious demon reiterated his death threat, believing the arrival of the Hashira's subordinates to be insufficient. Tengen remained confident in their victory, having deduced that cutting off both of the siblings' heads off at the same time was the key to success, but Gyutaro assured him it wouldn't be easy to accomplish. He also mentioned how he and his sister had eaten numerous Hashira, fifteen and seven, respectively. He then watched silently as Daki was taken onto the roof by Zenitsu, with Inosuke going to assist the towheaded youth in his fight, but remained confident that she would prevail. Utilizing his connection with his sibling, Gyutaro closed one of his eyes, and quickly attacked Tanjiro Kamado. He nearly struck a blow to the youth's neck, but was thwarted by Tengen at the last second causing him to only stab him in the chin mere inches away from the fatal strike, and proceeded to exchange a flurry of blows with his opponent. In the middle of this clash, sashes from his sister's conflict above them descended, prompting Gyutaro to call Tengen's claim of success to be a lie, as well as labeling his adversaries as incompetent for lack of movement control.

The Demon Slayers can be seen engaging in battle with the two demons of the Entertainment District, fighting ferociously on the rooftop and inside one of the brothels. As the building begins to collapse, Tengen finds himself getting cornered between two of Gyutaro's attacks however Tanjiro jumps in and manages to protect him from the slashes. Tengen proceeds to use Sound Breathing, Fifth Form: String Performance to try to corner Gyutaro, but Daki's obi interferes and protects her brother from the attacks.

Tengen begins to be pushed back by the obi, however Tanjiro moves in to cut the obi and tries to distract Gyutaro. Meanwhile on the rooftop, Inosuke and Zenitsu can be seen struggling as they try to evade the attacks from Daki's obi. The boys realize that Daki is know attacking them with the blood blades used by Gyutaro, making it impossible for them to approach her. Now that the brothel has been destroyed, Tengen and Tanjiro are left to fight Gyutaro and the obi beneath the night sky. On a nearby rooftop, Hinatsuru appears carrying a large box filled with kunai darts and proceeds to launch dozens of them down below onto Gyutaro. At first he is left confused behind the random attack, but then Gyutaro utilizes his Blood Demon Art: Rampant Arc Rampage to deflect them away from him. Gyutaro is left shocked when Tengen proceeds to attack him despite getting pierced with the darts. He attempts to decapitate him with his sickle, however Tengen manages to evade his attack and successfully cut off his legs. At that moment, Gyutaro is struck on the neck by one of the kunai darts and fails to regenerate his feet, realizing that the darts were coated with wisteria extract. As his body begins to go numb, Tanjiro closes in on him to try to decapitate Gyutaro, leaving him seething with curiosity as the Demon Slayers quickly gain the upper hand.

However at that moment, Gyutaro manages to regenerate his legs and proceeds to attack them at a close vicinity. He uses his Blood Demon Art, Rotating Circular Slashes: Flying Blood Sickles to emit numerous blood slashes to attack them. Before they can reach him, Tengen Uzui grabs hold of Tanjiro and throws him back to protect him from the attack. Within seconds, Tengen uses Sound Breathing, Fourth Form: Constant Resounding Slashes to deflect Gyutaro's attack but finds that he has disappeared from sight. To his horror he looks up to roof to see that Gyutaro has managed to capture Hinatsuru and is about to kill her.

Tengen tries to save her however Daki's obi blocks him from reaching her. Tengen yells at Gyutaro to stop as he tries to push through. Tanjiro comes close to the building and tries to use the Hinokami Kagura to reach her however his body refuses to listen to him. Tanjiro quickly changes tactics and uses a form of the Water Breathing to quickly save Hinatsuru from Gyutaro. Realizing that he managed to save Hinatsuru, Tanjiro decides to utilize both the Water Breathing as well as the Hinokami Kagura in order to increase his attacking power. Gyutaro is left surprised by Tanjiro's unexpected maneuver and charges at him. However at that moment, Tengen comes behind Gyutaro and swings his blade at Gyutaro's neck while openly yelling that he owes Tanjiro. Tanjiro assists Tengen by also trying to swing his blade down onto Gyutaro's neck, however the demon manages to use his sickles to halt both of their attacks and attempts to absorb their blades. Tengen uses his free arm to use his second blade to pierce the Gyutaro, but his quick reflexes allow him to catch the tip of the blade in his mouth. Sensing that Gyutaro is about to unleash more blood blades, Tengen tells Tanjiro to hang in there as Hinatsuru yanks Tanjiro away from them, allowing Tengen to leap off of the roof while pulling the demon with him.

As Inosuke runs away with Daki's decapitated head, Gyutaro suddenly appears behind him and impales him through the chest. Tanjiro looks on in horror as Gyutaro grabs Daki's head while Inosuke collapses on the roof, he then looks down on the ground and is once again horrified to see Tengen laying bleeding and unresponsive on the ground. Zenitsu tries to warn Tanjiro of the oncoming obi attack, but before he can escape, the roof collapses from beneath him and Tanjiro falls to the ground seemingly buried beneath the rubble.

Tanjiro awakens from his dream and tries to recollect his thoughts but before he gets up, Gyutaro can be seen standing over him, questioning if he's still alive. Gyutaro takes it upon himself to tell Tanjiro that Inosuke was pierced through the heart, Zenitsu was suffering and trapped beneath the rubble, and Tengen's heart had stopped due to the poison. He proceeds to refer to all of them as pathetic and asks Tanjiro how the demon in the box is related to him, and he responds by saying she's his younger sister. Gyutaro begins to laugh at Tanjiro's pathetic attempt to protect his sister and tells him he should be using his hands, before proceeding to break his fingers.

As Tanjiro withers on the ground in pain, Gyutaro proceeds to berate him for his weakness and pulls him by the hair. He teases Tanjiro and tells him to try to decapitate him, but instead of attacking him, he slaps his hand on a small bag and hangs his head down in defeat. Believing that he broke Tanjiro's fighting spirit, he reveals his grand idea of offering Tanjiro the opportunity to become a demon for the sake of his sister. Tanjiro suddenly looks up into the sky and Gyutaro asks him if he's trying to hold back his tears but to his surprise, Tanjiro responds that he had been preparing for the moment.

With his face gets close to Gyutaro's, Tanjiro brings his head down and headbutts him with a great force momentarily stunning him. Daki screams at him to get up but as his legs falter, and looks down to discover that a kunai dart has been lodged into his leg. Tanjiro manages to stand up while Gyutaro remains paralyzed and crouched before him, and uses his remaining strength to swing the blade down onto his neck.

Having regained his footing and subdued Gyutaro, Tanjiro manages to draw his blade onto Gyutaro's neck and press down to try to decapitate him. As he tries to force the blade down, Tanjiro envisions himself in Gyutaro's place and thinks that if he were in his situation, he would want his comrades to kill him before he could live as a demon. Tanjiro continues to struggle to try to cut through Gyutaro's neck but before he can do so, Gyutaro manages to emit his blood blades to repel his sword. Tanjiro is knocked off balance as Gyutaro regains his footing, causing them to reengage in battle. Gyutaro gains the upper hand and brings his sickle down onto Tanjiro's neck, however at that moment Tengen, regains his consciousness and protects him from the sickle.

Despite being severely poisoned and missing his left hand, Tengen engages in head to head combat with Gyutaro while remarking that he's perfected the Musical Score Technique. It is revealed that his technique allows him to analyze maneuvers of his opponents and read them like notes on a piece of sheet music. However the poison has hindered his attacking ability meaning that he can only defend Gyutaro's attacks.

Gyutaro manages to land a powerful attack to the left side of Tengen's face resulting in the loss of his left eye, and proceeds to stab Tengen. Tanjiro yells out to Tengen after witnessing him get stabbed, but Tengen orders him to ignore him and jump. Tanjiro leaps into the air towards Gyutaro and attempts to decapitate him, but is seemingly stabbed through the jaw by Gyutaro's sickle. The demon begins to panic as they gain the upper hand and pulsate his poison to try to kill Tanjiro, however he proceeds to endure the pain, and swings his blade towards Gyutaro.

It is revealed that the demon siblings were able to keep the Demon Slayers at bay through a hidden ability. During the battle, Gyutaro was controlling his sister and was able to see through her point of view, giving them the advantage. His poison also affected the Demon Slayers greatly, but there was always a member of the team that would slip through, allowing them to continue the fight. Tanjiro can be seen swinging his blade down onto Gyutaro's neck, despite the demon's sickle piercing through his jaw. His arm strength isn't enough to slice through his neck so he resorts to forcing his entire body to push through, ignoring the pain. Gyutaro notices the change in Tanjiro's scar as he develops a Demon Slayer Mark and his eyes roll back in his head. The change in his demeanor proves to be too great as Tanjiro's blade cuts through Gyutaro's neck, causing him to panic.

Meanwhile, Daki can be seen resisting Zenitsu's attempt to decapitate her. She attempts to use her obi to kill Zenitsu at close range, but Inosuke unexpectedly rushes up revealing that he protected his heart from being stabbed by rearranging his organs. He also reveals that poison has no effect on him since he was raised on the mountains, before proceeding to assist Zenitsu in decapitating Daki. The three boys let out a roar as they muster out the strength to slice through the Demons necks. After the long battle, Zenitsu and Inosuke manage to decapitate Daki up on the rooftop while Tanjiro can be seen decapitating Gyutaro simultaneously on the ground. Their heads fall onto the ground and roll around until they end up face to face.

As Gyutaro's body falls onto the ground, Tengen notices something being emitted from it and becomes alarmed. Meanwhile up on a nearby rooftop, Suma, Hinatsuru, and Makio have arrived to witness the end of the battle. As Makio begins to bicker with Suma over her behavior, Hinatsuru notices something is amiss down on the battlefield. She looks down to see Tanjiro struggling to breathe as he bleeds out from his jaw, while trying to slow down the poison. Tanjiro looks over at Tengen who's sitting down in front of him and yelling at him with a panicked expression. However, Tanjiro fails to comprehend his sudden alarm as Tengen looks at him with horror.

After the battle is over, Nezuko and Tanjiro search for the heads of the Upper Rank siblings. Tanjiro smells the scent of the demons and guides Nezuko to head towards them. When they arrive, Gyutaro and Daki can be seen viciously arguing over their defeat. Their heads begin to disintegrate as they blame each other for losing the battle, with Gyutaro degrading Daki for being useless. Daki retaliates by saying that someone as ugly as Gyutaro cannot be considered her relative, which leaves Tanjiro looking at them concerned about the hurtful words they are spewing at each other.

Daki and Gyutaro continue arguing as their heads begin to disintegrate, she starts chastising her brother for being useless and questions if they're even related. Gyutaro grows angry at her comments and calls her a weakling, even regretting protecting her in the first place. He loses his temper and goes on to spew hateful remarks such as mentioning that his life would've been better without her and wishing that she had never been born, causing Daki's eyes to well up with tears. Tanjiro intervenes and covers Gyutaro's mouth, stating that he doesn't mean what he's saying and that they shouldn't spend their final moments fighting with each other. Daki begins to wail at Tanjiro out of frustration, yelling at him to leave them alone and stop lecturing them. Daki's head reaches its last phases of disintegration and she cries out for her brother to save her, saying that she doesn't want to die. Gyutaro hopelessly watches as her head dissolves away while still calling out him, before he impulsively calls out to her by her birth name, Ume; he then remembers how his sister's name was never "Daki", but instead "Ume", referring to "Daki" as a horrible name.

In his final moments, Gyutaro reflects on the numerous hardships he faced. He remembers that his life was always pain and misery, being born in a time when children weren't valued and having a hideous appearance in a place when beauty was a measure of worth. Though Ume's birth gave his life a new meaning, one where he prided himself in her beauty and his own ugliness gained him a new reputation as a brutal, monstrous debt collector, the ruthless immolation of Ume once again brought pain to his life, and the realization that their lives were never fair only hardened his heart towards anyone living better than them. He acknowledges that he will always be "the Gyutaro who collects" but is able to see that his sole regret in life was raising Ume into the person she became.

With his death, Gyutaro's spirit appears in the afterlife, where he is shortly after joined by Ume. Gyutaro repeatedly tries to force her away from him, seeing that it is the only way for her to move into a better life; he even denies that they were ever siblings and urges her to move to the light of the other side. Ume ignores Gyutaro's words and holds onto him, tearfully refuses to be apart from her brother and reiterating a promise they had to each other where they would never be apart again. Having accepted her wishes, Gyutaro enters the fires of Hell with Ume.