Hikari Kyoudo vs Ikigai Kyoudo

**Hikari Kyoudo vs Ikigai Kyoudo** is a battle that takes place in the Infinity Castle during the Infinity Castle Arc. It is a long and extensive battle that focuses on the final interaction between Sky Hashira Hikari Kyoudo and the newly-appointed Upper Rank Three Yūgen.

## Prologue

After being separated from his fellow Hashira, Hikari wanders through the Infinity Castle until he finds a peculiar room marked with a crucifix. Hearing pained cries echoing from the room, Hikari enters and immediately draws his sword. The cries silence immediately, and a mocking laugh takes their place. Hikari uses **Sky Breathing, First Form: Sun's Province** to identify any obstacles hidden in the dark room, and a hand appears from the mist, catching all three of Hikari's rays.

A figure steps out from the mist, revealing the hand and laughter to be that of the now-primary Upper Rank Six, Yūgen. Yūgen laughs again at Hikari, remarking that his fear is a glorious sight to behold. Hikari demands to know who had been crying out for help just a few moments ago, and Yūgen states that they were of her own to distract Hikari from the real mission, which is to kill her.

Hikari curses Yūgen for enjoying the fear and suffering of others, stating that her disregard for life is appalling and refuses to believe she was ever a human. He says that no matter how many years a demon lives for, if they disregard a life and laugh at the pain of others, they don't deserve to remember their human past.

Yūgen remarks that if she had been a demon for less time, maybe she would have a sliver of human reason left. But since it had been so many years, she didn't care for it anymore, further enraging Hikari. Hikari demands that Yūgen stops spewing nonsense about not caring for human reason, and Yūgen responds with saying she will have to kill Hikari in order to be free from his own stupidity.

## Battle

### Until Our Paths Collide

Yūgen attacks first with her **Blood Demon Art: Violet Ripples of Darkness**, which Hikari deflects with **Sky Breathing, Fourth Form: Brewing Storm**. However, Yūgen alters her technique so another round of slashes direct towards Hikari, with three of them hitting him and leaving deep gashes across his left arm. Hikari doesn't let this slow him down, and retaliates with **Sky Breathing, Sixth Form: Rainstorm**. Yūgen blocks his strikes with her crucifix, and uses **Blood Demon Art: Pointed Snowflakes of Indigo** to attack Hikari. The attack slashes across Hikari's face, leaving him with deep scratches across his nose and his cheeks, but still this does not faze him. He hits back with **Sky Breathing, Third Form: Strike of the Sky**, managing to slice Yūgen in half. Unluckily for him, Yūgen regenerates almost immediately and laughs at his failure to kill her.

While fighting Hikari in close combat, Yūgen remarks that Hikari's strength and willpower is incredible, and could be harnessed to an even better level if he became a Demon and fought against his comrades. Hikari retorts that Yūgen is out of her mind and an absolute imbecile, since her suggestion to fight against the Demon Slayer Corps and the Ubuyashiki Family was outlandish to him. He says that he is glad their paths had never collided before, and that this was the last time they ever would.

After Hikari says this, Yūgen reveals that the two of them had indeed met before. She explains that Hikari himself had fought her in the battle that killed his father, Kintsugi Kyoudo, who was also the previous Star Hashira of the Corps. Yūgen expresses her sadness to the fact that Hikari had not followed in Kintsugi's footsteps and had instead mastered his own Breathing Style. She suggests that Hikari was too weak and inexperienced to master Star Breathing, and therefore branched off of it just like the first Breathing swordsmen of the Sengoku period.

### The Fourth Most Powerful Demon in Existence

Yūgen's mockery enrages Hikari, and he quickly jumps away from Yūgen and uses **Sky Breathing, Second Form: Clouded Vision** to confuse her and manages to reach Yūgen's neck, driving his blade through it. However, he only gets halfway through her neck when she grabs his blade and throws it away, and Hikari notices that the number in her eye had changed from Six (陸 *Roku*) to Three (参 *San*), marking Akaza's death and Yūgen's usurpation. As Hikari retrieves his blade from where it had been thrown, he looks on in horror as Yūgen awakens her full power after finally gaining the rank she was equivalent of after over three hundred years.

Although not much changes about Yūgen's appearance, it is clear to Hikari that she is now a lot more powerful than she was a moment ago, and he readies himself to strike her again. He leaps towards Yūgen to use **Sky Breathing, First Form: Sun's Province**, but Yūgen easily punches him away from her and breaks three of his ribs while doing so. She attacks Hikari with simultaneous attacks of **Blood Demon Art: Bloodstained Petrichor** followed by **Blood Demon Art: Tainted Blossoms of Hinami**, severely injuring him. While she attacks him, Yūgen proclaims and brags about now holding the title of Upper Rank Three, one she had waited to hold for hundreds of years. She says that she is now officially the fourth most powerful demon in existence, and Hikari dying to her would be 'a true honor' and a noble death.

Yūgen's bragging only drives Hikari to want to kill her more, and he goes to strike Yūgen again with **Sky Breathing, Fifth Form: Spotless Sky**, which Yūgen effortlessly deflects and retaliates with **Blood Demon Art: Blessed Insouciance**. As Yūgen's crucifix flies back to her, Hikari turns and sees the point driving towards his neck, and his life flashes before his eyes.

### Star Hashira, Kintsugi Kyoudo

In his flashback, Hikari finds himself watching his father Kintsugi perform Star Breathing techniques, and realizes he is reliving the day his brother Kiyoi was poisoned. The flashback shows Hikari repeating his father's techniques over and over again, until a call from his mother summons them both inside their household. Hikari and Kintsugi find Hikari's mother with an unconscious Kiyoi in her arms, and she explains that Kiyoi had been poisoned by a mysterious stranger while he was out collecting taxes. Hikari takes Kiyoi into his own room in the house and attempts to cure him, but only manages to save him from imminent death.

As the night passes, Hikari is sent outside to train with his father again, and re-performs more Star Breathing techniques. However, almost immediately after he stops practicing the Breathing Style, the flashback cuts to the night Kiyoi dies, and he says his final words to Hikari. Kiyoi says that Hikari shouldn't trouble over him, since he knew he was going to die no matter what. Although Hikari begs Kiyoi not to go, and to try and stay alive just long enough for him to figure out how to save him, Kiyoi says he knows it's too late and that Hikari did what he could.

Suddenly, Hikari is brought to the scene that was the ending of his and his father's fight against Yūgen, and he watches his father perform the final form of Star Breathing while awakening his Demon Slayer Mark. Once he sees this, he is thrown out of his flashback and awakens his own Demon Slayer Mark, which was exactly the same as Kintsugi's. He asks his father to forgive him for not following in his footsteps, and destroys Yūgen's crucifix with his blade.

### Starlight Ascension

Hikari turns back to Yūgen with anger in his eyes, his Demon Slayer Mark glowing across his face. He tells Yūgen that this fight will end with her head being disconnected from her shoulders, and rushes forward and slices Yūgen in half a second time using **Star Breathing, Fourth Form: Bright Rain of Stars**. Yūgen takes a while to regenerate, since the Breathing technique burned away some of her body. As Hikari looks back, he manages to access the Transparent World and notices a second cell inside Yūgen's heart. He goes to stab her through it, but she is quick enough to defend herself. Enraged, Yūgen attacks Hikari with **Blood Demon Art: Essence of Devilish Poison**, but Hikari blocks the attack and uses **Star Breathing, Third Form: Purgatory Light** to distract and decapitate Yūgen.

After Yūgen's head falls to the ground, Hikari prepares to rest and check over his wounds, but rays of Yūgen's poison fly at him and hit his arms, almost tearing them off and leaving deep slashes down his shoulders. Hikari realizes that Yūgen, despite being decapitated, was still able to attack him, meaning she wasn't dead and there was another way to kill her. Hikari prepared his sword, blocking the rest of the rays Yūgen threw at him and eventually jumping forward with **Star Breathing, Sixth Form: Blessed Whirlwind**. Right as Hikari goes to strike Yūgen, her head regenerates and she stabs him with her newly-made crucifix, tearing his left arm off. Hikari falls back, attempting to prevent himself from bleeding out but knowing he wouldn't have much time to live if he didn't do something now.

As Hikari continues to dodge Yūgen's rays, he realizes that she has the same blue ribbon around her wrist that he had around his own hand. He asks her where it is from, and Yūgen stops attacking him. Yūgen cries as she remembers her father Ren, who had gifted her and her brother both a blue ribbon to pass down through the generations, with only her brother carrying out the now ages-old tradition. Hikari goes to attack Yūgen in her vulnerable state, but stops as he sees her tears. He goes to ask her why she was crying, and apologizes if it was his fault, and Yūgen lashes out at him saying she was supposed to fulfill the tradition, but her brother did instead and he was the reason Hikari had the blue ribbon. She cries out saying it was unfair that she became a demon since she was destined to help others with her gift. She then reveals that her gift was a healing property abused and exploited by the people around her, and she falls to her knees in grief.

Hikari tells Yūgen he understands what happened to her since the same thing happened to him, but Yūgen argues saying he would never understand the betrayal it took for her to get where she was now no matter what. She stands back up and prepares to attack Hikari again, this time more driven to kill him.

### Forgive Me, Ren

Yūgen activates the final form of her Blood Demon Art, **Kiyoi**, now even more powerful. She yells that her name is Yūgen and that she is Upper Rank Three of the Twelve Kizuki, before leaping at Hikari and preparing to engage in close combat against him. Hikari uses **Star Breathing, Seventh Form: Kiyoi** in unison, regenerating his lost arm and also jumping at Yūgen. The two of them strike each other and continue to attack, Yūgen using multiple forms of her Blood Demon Art simultaneously as well as Hikari using multiple Star Breathing techniques. Once the two fall away from each other, Hikari grips his sword and links his Demon Slayer Mark with it, turning the blade bright red before taking a low stance and awakening Star Breathing's **Unspoken Form**, the same as his father had done years ago against the same opponent.

The two of them engage in distant combat, Hikari unleashing multiple Star Breathing techniques as well as sending streams of light towards Yūgen and burning her. Yūgen retaliates with multiple forms of her Blood Demon Art, sending rays of poison towards him. Most of them miss, but the ones that hit dissipate into his bloodstream and therefore poison him. Hikari knows he would be weakened by the poison and the caliber of the Unspoken Form, but he continues to drive closer and closer to Yūgen until he sets his blade alight with his technique and decapitates her.

## Aftermath

As Yūgen's head falls to the ground along with her body, Hikari effortlessly lands still on the floor, dropping his sword and collapsing out of exhaustion. He lays on the ground, watching Yūgen's head slowly disintegrate. Yūgen cries, apologizing for killing Hikari's remaining family and saying she regrets every action she had ever taken against him. She also apologizes for burdening her brother with passing down the age-old traditions she was tasked with, and says she is sorry for being such an awful sister. She finally apologizes to her father for becoming a demon and breaking their promise of always being on the side of what is right, and for killing thousands of people over her 345-year lifetime. As she fades away, she whispers to Hikari that her name was never Yūgen, and it was Ikigai Kyoudo.

All that is left of Ikigai is the blue ribbon she had tied around her wrist. A gift from her father that was meant to be passed down through generations was kept pristine for hundreds of years. Hikari reaches out and takes the ribbon, tying it over his own ribbon and reassuring the now-deceased demon that she was forgiven.

Ikigai is reunited with her father and her brother in Hell, and apologizes profusely for her regrettable actions. Meanwhile, Hikari is slowly suffering from the effects of Ikigai's poison, and lays still and attempts to slow them.