Izuku Midoriya grabs hold of Mirio Togata's cape, reels the cape in and grabs hold of Eri, promising her that he will not let go of her this time. Infuriated, Kai Chisaki demands that Izuku hand Eri back to him and charges at him. Izuku isn't able to move well suspended in mid-air. However, Izuku vows to not let go of Eri no matter what and remembers Mirio's question of what Hero he wants to be; he wants to be a Hero that wipes everyone's worries aways, always wins and saves everyone.
Filled with utter determination, Izuku unconsciously activates One For All 100% and prepares to attack Chisaki with a kick, while Chisaki launches reconstructed stone pillars at Izuku. As Chisaki's stone pillars begin to ensnare him, Izuku disappears and the ceiling above them collapses as a shockwave ensues.
The collapse of the ceiling and the resulting shockwave was caused by Izuku launching himself out of the Shie Hassaikai's basement using One For All 100%'s wind pressure. Izuku himself realizes that he traveled through the air at high speed using One For All 100%'s generated wind pressure, similar to All Might's New Hampshire Smash and in the process smashed himself out of the basement. However, Izuku's legs are completely broken as a result.
Back in the Shie Hassaikai's basement, Ryukyu's group are in confusion as to what occurred. Chisaki gets up and is injured of the shockwave caused by Izuku's One For All 100%. Having become desperate in getting Eri back so that he can realize the Shie Hassaikai boss's ambition, Chisaki uses his Quirk on Rikiya Katsukame and fuses with him.
Ryuko Tatsuma prepares for battle, but a badly injured Sir Nighteye, who is being tended to by Tsuyu Asui, eases Ryukyu's worries as Chisaki is going to pursue Izuku and is intend on not only getting Eri back but murdering Izuku as well. Ochaco Uraraka plans to go to Izuku's aid, but falls down due to her stamina being drained courtesy of Rikiya's Quirk.
Despite Sir Nighteye's prediction, Ryukyu refuses to let Chisaki go after Izuku. However, Sir Nighteye convinces her that her group cannot hope to defeat the newly fused and empowered Chisaki. Ochaco refuses to stand by and do nothing. Sir Nighteye asks Tsuyu to tend to Mirio and for Ochaco and Ryukyu to help him to the surface.
Surprisingly, Izuku manages to land on the ground safely despite his legs being broken. However, Izuku realizes that his legs are not broken and have in fact being healed, surprised that despite using One For All 100% his body along with all his injuries have been healed. Izuku realizes that his healed body is thanks to Eri's Quirk ability.
Suddenly, Izuku begins feeling the immense recoil of One For All 100%. Chisaki appears and states that Eri has unlocked her power but doesn't know how to stop it and launches reconstructed pillars at Izuku to which he dodges. The newly fused Chisaki appears, looking similar to a stone dragon.
From the dragon's maw, Chisaki appears and reveals that Eri can rewind humans and depending on how she controls it, she could revert a human back to a monkey or even to nothingness, calling her Quirk a curse and warns Izuku that holding onto Eri is dangerous, which is why he is demanding that Izuku returns Eri to him because only with his Quirk can he stop Eri's cursed Quirk.
Izuku vehemently refuses to hand back Eri and will hold onto her no matter what. Having experienced Eri's Quirk, Izuku sees that the moment his legs broke Eri reverted them back to normal before he could experience any pain and thinks that Eri's Quirk is a kind, gentle Quirk contrary to Chisaki's thoughts, which shocks Eri.
Understanding that Eri's Quirk reverts any pain and grievous damage back to normal at blinding speed, Izuku decides that he doesn't need to hold back since all major recoil and damage accumulated by his Quirk will be continuously reverted and healed thanks to Eri's Quirk, therefore not needing to worry about turning into nothingness.
Izuku asks Eri if she will lend him her power and, going all out, activates One For All: Full Cowl: 100%.