Red Scale

Racing toward the station, Yuji spots transfigured humans attacking civilians below and agonizes over whether to help when he has no time to spare. A familiar coded phrase reaches him, Toge Inumaki has arrived, and Yuji hands the rescue off to his upperclassman before pressing on. Toge unzips his turtleneck, pulls out a megaphone, and turns his Cursed Speech on the monsters. Inside the eerily empty station, Yuji descends a stairwell and comes face to face with Choso, who instantly fires Convergence Piercing Blood, punching clean through Yuji's left arm before he twists away to keep it attached.

The fight escalates as Choso pours out massive volumes of blood, summons Flowing Red Scale, and bombards Yuji with waves, spikes, and a Supernova buckshot that shreds his back. Yuji learns to bait the slow follow-up shots of Piercing Blood, but Choso keeps adapting, even stabbing Yuji's feet with a blood dagger. Heavily injured, Yuji recognizes he is outmatched. Then Mechamaru's relay device speaks up again, identifying Choso's power as the same Blood Manipulation used by the Kamo clan.

Mechamaru does not know the technique's weakness but proposes a long-shot plan, telling Yuji to retreat into a bathroom whose sprinklers and faucets have been rigged to spray water everywhere. He taunts Choso into following, and once inside, the water dispels Convergence and detonates Choso's floating blood orbs, since the technique keeps blood from clotting and so dissolves in water. Forced to rely on Flowing Red Scale: Stack, Choso controls only the blood inside his body, dragging the duel into the close-quarters range where Yuji is comfortable.

The two trade vicious blows, with Choso hiding a tooth as a feint and hardening his fist and forearm into weapons. He fires a hidden Blood Meteorite into Yuji's liver, then cracks his collarbone with a hammer fist and finishes him with a crushing strike that hurls him into a wall. Sukuna watches from his domain, calling Yuji worthless for losing. As Choso moves to execute the unconscious student, a fabricated memory floods his mind, a peaceful picnic with all his brothers and Yuji among them, who feeds him and calls him big bro. Shaken and spitting blood, Choso stumbles away, and Mimiko and Nanako appear over Yuji's body.

The episode adapts chapters covering the Yuji versus Choso fight. Yuji converts his fear into cursed energy mid-battle, resolving to help save Gojo even at the cost of his life. The fabricated memory is the seed of Choso's later turn. The anime greatly extends both the hallway and bathroom phases of the fight, adding Choso crushing the relay device, temporary blood weapons that blind Yuji, and the missed execution punch that destroys the wall instead.