Demon Slayer Chapter 171

Demon Slayer Chapter 171, titled "Transformation," plunges deeper into the Infinity Castle battle, witnessing Genya Shinazugawa's alarming demonic evolution, Kokushibo's terrifying blade transformation, and the desperate struggle of Gyomei Himejima and Sanemi Shinazugawa against the Upper Rank One. After consuming Kokushibo's hair, Genya begins to convulse and breathe heavily, his arm eerily reattaching as a voice rings in his head. He questions the voice, realizing his torso has reconnected and he is healing rapidly, pondering the concentrated power of Upper Rank One's blood. As his circulation accelerates, he sees a broken piece of Kokushibo's katana, and the voice, which he recognizes as Muzan's, warns Kokushibo not to let the Hashiras get close, making Genya wonder about his own fate if his demonic transformation continues in the thrilling narrative of the Demon Slayer manga.

Meanwhile, Kokushibo, still fighting Gyomei and Sanemi, surmises they are the strongest of their generation, particularly highlighting Gyomei's unparalleled physicality and his unique weapon that uses chain vibrations for spatial awareness. Deciding to destroy Sanemi's katana first, Kokushibo aims to strike it on its side to shatter it easily. Sanemi intercepts the slash, driving Kokushibo's katana into the floor. Kokushibo lunges back to avoid a retaliatory slash from Sanemi that cuts off some of his hair, noting Sanemi's accelerating and more precise movements despite his injuries and the Demon Slayer Mark. Gyomei suddenly appears, slashing his axe upwards and severing Kokushibo's ear. Sanemi follows with Wind Breathing, First Form: Dust Whirlwind Cutter, creating a separation. Together, Sanemi and Gyomei execute a combined attack, using Wind Breathing, Seventh Form: Gale, Sudden Gusts and Stone Breathing, First Form: Serpentinite Bipolar, ripping off Kokushibo's kimono, a moment of fleeting success against their formidable foe.

As they leap back and prepare for another attack, aiming for Kokushibo's head, the Upper Rank One simply stands, encouraging them. Before they can get close, Sanemi and Gyomei are suddenly covered in numerous slashes. Gyomei questions how Kokushibo managed to attack at range and watches in horror as Kokushibo reveals his katana, now greatly extended and sporting three new cutting edges along its main blade, a horrifying testament to his continuous demonic evolution. Kokushibo dismissively claims they merely shredded his kimono, "not even enough to kill an infant," and chillingly remarks that after killing the two Hashiras, everyone else will be dispatched with ease, setting the stage for an even more desperate and brutal phase of the battle in the climactic Infinity Castle Arc of the Demon Slayer manga.