Demon Slayer Chapter 137

Demon Slayer Chapter 137, titled "Undying," marks the chilling culmination of Muzan Kibutsuji's infiltration plans, as he confronts a dying Kagaya Ubuyashiki, revealing the tragic history of the Ubuyashiki clan's curse and the profound power of human emotion in the face of eternal evil. Despite his blindness, Kagaya knows Muzan now stands before him—the demon his clan and the Demon Slayers have pursued for a thousand years. He asks Amane to describe Muzan; Amane tells him the demon appears as a man in his mid to late twenties, with light pink eyes and cat-like slits for pupils. Kagaya calmly remarks he had expected Muzan's appearance, believing the demon's deep-seated anger towards his clan has finally driven him to kill Kagaya personally, setting a tense and grim atmosphere for their long-awaited confrontation.

Muzan confirms Kagaya's assumption, expressing his profound disgust at the Ubuyashikis' continuous intervention throughout his existence, yet finding their current leader in such a deplorable state. He callously insults Kagaya, deeming him loathsome, indescribably ugly, and already possessing the scent of a corpse. Kagaya, surprisingly, agrees with Muzan's sentiment, revealing that six months ago, his physician had only given him days to live, yet he has defied death until now, fueled by his burning anger and resolve to defeat Muzan. Muzan retorts that all of Kagaya's efforts will be futile once he kills him. The Oyakata then makes a shocking revelation: they are actually of the same bloodline, a fact Muzan, born a millennium ago, would not have known. Muzan dismisses this, asking why Kagaya is telling him, to which Kagaya explains he is the reason for his family's curse. Because the Ubuyashiki clan bore such a monster as Muzan, their bloodline was cursed, causing its children to grow weak and die young. As the clan faced extinction, a priest approached them, explaining that a demon was born in their bloodline and that by dedicating themselves to killing this demon, the clan would survive. Kagaya adds that he married Amane because her family had a long history in the priesthood. Following the priest's advice, the Ubuyashikis lived slightly longer, yet none had ever lived past the age of 30, underscoring the severity and persistence of the curse.

Muzan disregards Kagaya's story, questioning if his sickness has affected his brain. He claims Kagaya's history is irrelevant to the present, adding that the heavens have never punished him despite killing thousands of people; in his thousand-year existence, he has never encountered gods or Buddha, reinforcing his nihilistic worldview. Kagaya then asks Muzan what he truly dreams of, what he has desired for his entire life. Muzan ponders the strange situation; he has the Demon Slayer Corps' leader before him, yet he feels no personal hatred. Nevertheless, looking around the Ubuyashiki mansion and seeing Nichika and Hinaki playing blissfully unaware of his presence, he feels an odd familiarity—relieved yet disgusted by the fleeting glimpse of normalcy. When Muzan does not respond, Kagaya offers to answer for him: Muzan's dream is eternity and to be undying. The demon agrees, mentioning he will achieve this by finding and devouring Nezuko Kamado. When Kagaya asserts this dream will not come true, Muzan dismisses his confidence in hiding Nezuko, believing he has all the time in the world to search for her as Kagaya soon dies. Kagaya states he is mistaken, knowing that the only truly eternal thing is human feelings. Muzan vehemently denies this statement as rubbish, but Kagaya continues, emphasizing that for a thousand years, the Demon Slayer Corps has persevered despite countless deaths, a testament to the undying nature of human will.

Kagaya asserts that Muzan has just disregarded proof that human feelings are indeed undying: the unwavering refusal to forgive those who unjustly take lives. Up until now, no one has forgiven Muzan for his atrocities. He remarks that Muzan has metaphorically stepped on the tiger's tail, and by doing so, he is inviting the dragon's wrath. "It"—the collective will of humanity's fury—has remained dormant until Muzan awakened it, its eyes now fixated on him, vowing never to let him escape. Kagaya states that killing him is futile as he is of little importance, before taunting Muzan for his inability to comprehend the eternity of human feelings, as all demons will perish if Muzan dies, highlighting the interconnected fate of demons with their progenitor. Now visibly angered by Kagaya's taunts, Muzan stares silently at the dying leader, who realizes he has finally captured the demon's full attention. Finally, Kagaya adds that while his death is meaningless in itself, it is not insignificant; the Demon Slayer Corps and the Hashira are deeply fond of him, and should he die, they will be more motivated than ever before, setting the stage for their final, desperate assault. Muzan asks if the Oyakata has finished speaking, revealing his hand's claws, poised to strike. This dramatic conclusion to Demon Slayer Chapter 137 ignites the final battle against Muzan, driven by generations of human resolve and a dying leader's ultimate sacrifice, propelling the narrative into the climactic Infinity Castle Arc of the Demon Slayer manga.