Rage

Facing Muzan, Tanjiro feels a hatred colder than anything he has known, his whole being trained on the demon king. He reminds himself of their orders: stall Muzan until reinforcements come, drag the fight toward dawn, learn and relay anything useful about him, and above all stay alive long enough to manage it, for only then does the real battle begin.

Turning his arms into blades and hooks, Muzan tears into the pair and admires his own ferocity as he wrecks the surroundings. Giyu barely blocks with a Water Breathing form, noting the arms cut like swords, extend at will, and move with terrifying speed. Deciding he cannot rely on instinct alone, Tanjiro lunges past an attack to close the gap, only for Muzan to throw him off balance and slash his right eye, and he is nearly killed again before Giyu pulls him clear, warning that they need not strike a foe stronger than any Upper Rank directly.

Overhearing them, Muzan observes that sunlight cannot enter the castle and wonders how three Hashira mean to manage it. When the slayers react with alarm to his mention of three, Muzan claims that Obanai and Mitsuri have already fallen to Nakime, showing the vision his subordinate shares with him in which both the Serpent and the Love Hashira lie dead, a falsehood meant to crush their resolve.