Shin Nemoto/Synopsis

History
Shin used to be a hardened con artist, becoming aware of how people always masked their true nature and weaknesses, even if they were unaware of it themselves. Those he spoke to would always lie to him before Shin forced them to tell the truth, leading them to keep their distance from the con man as he grew further disillusioned.

Shin joined Shie Hassaikai after being intentionally scouted by them. Overhaul's villainous, yet honest intentions convinced Shin to accept his new purpose in life.

Shie Hassaikai Arc
Overhaul, Chronostasis, Shin, and another Shie Hassaikai member defeat Team Reservoir Dogs and destroy their getaway vehicle.

When Overhaul starts fighting the League of Villains, members of the Eight Precepts of Death come to his aid, including Shin. Tomura Shigaraki decides not to continue the fight, and the yakuza leave.

When Tomura and Overhaul come to an understanding, he lends him Himiko Toga and Twice as a sign of trust. Overhaul has Chronostasis, Mimic, and the Eight Precepts of Death all present. Overhaul asks Himiko and Twice what their Quirks are, but they refuse to say. Shin uses his Quirk and asks them again, forcing them to say what their Quirks were. He also asks if Tomura plans to betray the Yakuza to which Himiko and Twice both answer no.

When multiple Pro Heroes, their interns, and the Police Force invade the Precepts' HQ, the Eight Bullets are sent to fight the heroes to buy time for Overhaul to escape. Shin is teamed up with Deidoro Sakaki and they confront Mirio in the tunnels beneath the compound. Deidoro uses his Quirk to destabilize Mirio's balance, giving Shin a chance to shoot him with his gun, failing to do so due to Mirio's Permeation.

Shin uses his Quirk on Mirio, first to know about his Quirk, and later to break Mirio's will to fight convincing him that he is only saving Eri to make himself feel better, because he had to overlook her suffering so things could proceed smoothly. When Shin and Deidoro try to finish off Mirio, he regains his will by accepting his "sin", and his desire to make Eri happy overcomes their Quirk long enough to use his Super Move: Phantom Menace to defeat both.

After defeating Shin, Mirio engages in a fight against Overhaul to rescue Eri, and thanks to his combat skills and his Quirk he begins to impose on the leader of Shie Hassaikai. Even being completely subjugated by Mirio, Shin's devotion to Overhaul allows him to keep his consciousness and to drag himself to where Overhaul is. Overhaul throws a cartridge with special bullets at Shin and tells him to shoot.

Quickly remembering Mirio's strong devotion to save Eri, he fires at the girl, anticipating Mirio to jump in and take the the Quirk destroying bullet himself. Mirio does exactly this, covering Eri as the bullet is shot into his body which begins destroying Mirio's Permeation. Overhaul states that due to Quirks people are entitled to dream and begin thinking that they become people that matter, to which Overhaul believes that these people are sick in the head.

As Shin celebrates his triumph, Overhaul laughs at Mirio's efforts and mocks Mirio for smiling because everything he has worked so hard to cultivate has been reduced to naught. As Overhaul is about to deconstruct the ground, Chronostasis is thrown at him, courtesy of Mirio's kick. Mirio appears before Overhaul and punches his arm. Mirio tells Overhaul that all his hard work isn't in vain because he will still be Lemillion. Overhaul tries attacking Mirio but Mirio is still able to make his body intangible, which causes Overhaul to miss. Shin is shocked that Mirio's Quirk hasn't completely been destroyed yet.

Despite his statements and will, without his Quirk, Mirio is injured by Overhaul, and when he is about to being killed, Deku, Shota and Nighteye arrive at the scene. While Nighteye helps Mirio and Eri, Deku and Shota face Overhaul. With the help of Chronostasis, Overhaul manages to get rid of Shota, and uses his Quirk to bring Nemoto's unconscious body towards him.

Overhaul refuses to allow his plans to be ruined by the Heroes. Overhaul knows that Shin Nemoto also wants him to succeed and approaches him. Overhaul thanks Shin for everything he has done for him and knows fully well that he will gladly die for his sake. Overhaul uses his Quirk and destroys both himself and Shin. Overhaul and Shin's deconstructed bodies reconstruct and fuse together with Overhaul, much to Izuku's horror.

Overhaul admits that Mirio was stronger than him but his efforts will all be in vain. The fused and transformed Overhaul appears, looking monstrous and grotesque with sharp bird-like arms from his shoulder blades and his original arms becoming larger with sharp claws. The transformed Overhaul declares that Eri will be returning to him.

Under this monstrous form, Overhaul first confronts Nighteye, whom he seriously wounds, and then confronts Izuku, who despite being overcome by his enemy, fiercely fights against him. To confirm that his efforts are useless, Overhaul uses Nemoto's Quirk to get Eri back with him, with questions for Deku to understand that even the girl thinks she has no chance of rescuing her. Despite this, Deku refuses to give up.

At that moment, cheated by the League of Villains, suddenly, Ryukyu's team crashes through the roof with Rikiya Katsukame, creating a huge hole towards the surface. Overhaul decides to take advantage of that hole and creates a stone pillar with his Quirk that rapidly raise him to the surface with the girl.

Izuku refuses to let Chisaki get away with Eri and jump towards them. As they head for the surface, Eri notices Lemillion's cape flying through the air and is reminded of everyone's desire to save her. By instinct, she grabs the cape after remembering Mirio's kind words.

This triggers Eri's Quirk, Rewind, and she begins emitting strange energy from her horn. This energy rewinds Overhaul back to his normal form before he fused with Shin Nemoto.

Shin Nemoto is unconscious for the rest of the battle, in which Overhaul, in a desperate attempt to retrieve Eri, uses his Quirk to fuse with Rikiya, transforming into a grotesque creature of great strength. However, he is defeated by Deku when he uses 100% One For All in combination with Eri's Rewind.

After the defeat of Overhaul, Shin Nemoto is arrested by the police along with the other members of Shie Hassaikai.