Mirio Togata vs. Kai Chisaki & Hari Kurono is a battle fought between Pro Hero Sir Nighteye's trainee Lemillion against Shie Hassaikai members Overhaul and Chronostasis during the Shie Hassaikai Raid.
Disgusted, Overhaul wipes dirt from his face and orders Eri to return to his side. Overhaul reminds her that when she acts selfishly that he's the one who ends up with his hands dirty. He claims Eri was born to destroy others and she pleads with Mirio to run without her. Mirio tells her not to listen as Overhaul goes on to state that Eri is cursed.
Overhaul quickly reassembles the floor into a bed of spikes that collide into each other in an attempt to crush Lemillion and Eri. Mirio is surprised Overhaul would put Eri in harms away. Overhaul claims he can always restore Eri to her original form and implies that he's done it many times before. This enrages Mirio even further, but he's forced to keep dodging to keep Eri out of danger.
Overhaul tells Lemillion that he can't achieve victory because he can't escape with Eri. Overhaul sealed off any means of escape and he's the only one who can heal Eri if she's hurt. Chronostasis recovers and threatens to shoot Lemillion with a Quirk Erasing Bullet that will destroy his Quirk for good. Lemillion meant to knock out Chrono with his last attack but Deidoro's Quirk is still affecting him.
Chronostasis targets Mirio's arm that's cradling Eri while Overhaul erases his cover. Lemillion cloaks them both in his cape which throws off Chronostasis's aim. They land and Mirio secretly phases through the ground and takes Chronostasis by surprise with an uppercut. Lemillion's shoulder disarms Chronostasis, but the villain gets away unharmed after Overhaul extends the platform he was sitting on.
Chronostasis remarks that heroes wear capes to play tricks. Overhaul notices Mirio left Eri in his cape and moves to destroy her to ruin his morale. Lemillion anticipates Overhaul's strategy and calls him the worst kind of scum. Lemillion phases a strong right hook through Overhaul's defending hand and lands a direct hit to the villain's face. Lemillion proudly states that heroes wear capes to cloak tormented little girls in its comfort.
Lemillion watches hiss enemies closely so he can predict their next move. He admits that Overhaul doesn't fight like a small-time Yakuza. However, Lemillion still believes that he's even stronger than that. He phases through the ground and takes down Overhaul and Chronostasis before they can even react. Lemillion bodily states he'll never let Eri get hurt again, and proclaims "Chisaki" the loser. Overhaul demands Mirio stop using a name he threw away.
Determined to reunite with Overhaul, Shin drags his defeated body to the site of the skirmish. Overhaul opens a hole for Shin to enter and orders him to take the gun and the perfected Quirk Erasing Bullets and shoot. Shin knows that it took a long time to develop only a few of the perfected Quirk Destroying Bullets. He can't afford to miss one shot and decides to take aim to expose Mirio's weak spot for Eri.
Mirio knew immediately that Eri was bracing herself for the pain she was all too used to. Refusing to allow her to be hurt ever again, Mirio lunges himself in the path of the bullet and sacrifices his amazing Quirk for Eri with a smile. Overhaul prepares to attack and tells Mirio to wipe the smile off his face because the girl he's trying to save is the reason all his hard work has gone to waste.
Suddenly, Mirio launches Chronostasis' unconscious body at Overhaul to cover his advance. He delivers a strong punch that hurts Overhaul's defending arm. Despite losing his Quirk, Lemillion sticks to his guns and predicts Overhaul's movements. Mirio knows none of his hard work will ever go to waste and proudly shouts that he will always be Lemillion.
Irate, Overhaul dissolves the glove over his left hand and trusts it at Lemillion. Mirio evades it and delivers another direct blow to Overhaul's face. Shin watches on absolutely baffled by Mirio's strength. He can't fathom how Lemillion is able to fight despite losing his powers, Deidoro's Quirk weighing him down, and the responsibility of protecting Eri. Confused, Shin asks what in the world Lemillion is.
Mirio fights another third of the battle without his Quirk. Overhaul finally manages to injure him with a few spikes. Even so, Lemillion stands victorious, having protected Eri until the end. Overhaul tries to attack again, but Deku, Eraser Head and Sir Nighteye burst into the room. 
Deku breaks through the cave wall with a One For All: Full Cowl - Shoot Style Smash and immediately punches Overhaul away from Lemillion. Eraser Head tells Nighteye to secure the girl while he and Deku take on Overhaul. Mirio tells Sir Nighteye that Eri is behind him and Sir embraces them both. Sir Nighteye tells Mirio he did a splendid job
Anime and Manga Differences
- The anime adds additional scenes of Mirio fighting Kai after losing his Quirk.
- The anime cuts out the scene of Shin Nemoto crawling towards the fight between Mirio and Overhaul to help the latter.