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History
In the past, Metal Bat was a C-Class Rank 223 hero, but after impressing the Hero Association through his excellent performance against Demon-level threats, he was moved up to the S-Class one year before the current story. The association members offered to arrange anything he wished, listing things they have provided for other S-Class heroes, and tell him that he can request anything even specialized weapons if he so pleases. Metal Bat then requested a bat that would never break, as his previous bats constantly broke, and received his signature metal bat. He was later berated by his younger sister for not getting Sweet Mask's autograph.

Alien Conquerors Arc
Metal Bat attends the S-Class heroes meeting, where he openly complains about missing his younger sister's piano lesson. From there, he proceeds to fight alongside the other S-Class heroes against Melzargard. During their fight, Metal Bat repeatedly smashes the monster's flying head and managed to find and destroy the marble-like orb inside its head, killing the head. With the aid of Bang and other S-Class heroes, they are able to destroy all the marbles inside of it and kill Melzargard.

After the fight was over, the spaceship above them begins to crash down and they escape towards the headquarters. When Sweet Mask arrives and demands an explanation, Metal Bat and the other heroes explain the situation, but are met with Sweet Mask's criticism. Angered by his statements, Metal Bat threatens to start a fight with him, but before the tension can escalate, they are surprised by Metal Knight's arrival.

Monster Raid Arc
Metal Bat is tasked to protect Narinki, a VIP sponsor of the Hero Association, and his son Waganma at a Mouse Sushi restaurant in S-City. He tells Waganma to not put the dishes that he has finished back on the counter, but the child doesn't listen, much to Metal Bat's displeasure. Metal Bat soon receives a call from his sister; she asks if he can take her shopping, but declines because of his mission. His sister starts crying and hangs up the call. After the call, Metal Bat feels a sudden shaking. Metal Bat rushes back to Narinki and finds that Junior Centipede has emerged from the ground with Venus Mantrap. Furthermore, Junior Centipede had grabbed Waganma. Before the monsters can attack, Metal Bat grabs his coat and engages in a fight with the mysterious beings.

Metal Bat finishes his fight with Junior Centipede and Venus Mantrap. Narinki and his child Waganma are delighted and wish to celebrate. However, Junior Centipede is still alive and praises Metal Bat for his strength, but still questions Metal Bat about how high he is in the food chain. Before Metal Bat can finish Junior Centipede off, Senior Centipede erupts from the ground. Senior Centipede forces Metal Bat, Narinki, and his son out of the restaurant. Outside, Rafflesidon emerges from the ground and starts releasing sleeping gas. Narinki and Waganma immediately fall unconscious, and Metal Bat is left to fight two Demon-level monsters. During the battle with Senior Centipede and Rafflesidon, Metal Bat temporarily comes under the influence of Rafflesidon's gas. Senior Centipede takes advantage of his drowsiness and strikes him several times. However, Metal Bat hits himself in the head with his own bad, allowing himself to stay awake. After regaining control, Metal Bat proceeds to defeat Senior Centipede and Rafflesidon with one strike each. However, only after the monsters are defeated does Metal Bat remember that he was supposed to interrogate them.

After the Demon-level monsters are defeated, Pineapple and Mohican arrive at the scene. Metal Bat asks them to bring Narinki and Waganma to the hospital so that he can finally help his sister with her shopping bags. However, Elder Centipede emerges, breaking the ground. The lower class heroes inform Metal Bat about the monster, stating that it previously wiped out a town and it is marked as a Dragon-level monster. Metal Bat tells the two other heroes to grab the sponsor, his child and run, while he prepares to go battle. Metal Bat intercepts Elder Centipede with a swing of his bat when the monster is charging at Pineapple and Mohican, but his attack does not even leave a scratch and he is launched into a building. Metal Bat then realizes that the monster's face is its weak point. He jumps onto Elder Centipede while the monster continues chasing Pineapple and Mohican. Before Elder Centipede is able to reach them, Metal Bat unleashes an attack on Elder Centipede's head. Elder Centipede then tries to shake Metal Bat off by maneuvering around the city. Metal Bat is launched hundreds of meters across the city, hitting the ground. He gets up, but is confronted by Garou, who proceeds to attack him. The Hero Association tries to contact him but is unable to do so, due to the fact that Garou is fighting him. Garou is able to hold back against Metal Bat, who is now much stronger than before, due to his extensive training and is already able to see Metal Bat's attack patterns. Garou comments that he is disappointed on being unable to fight Metal Bat at his best.

Metal Bat retaliates with an attack, but Garou manages to dodge it. The hero hunter is surprised by Metal Bat's persistence despite his numerous injuries, but insists that Metal Bat is at his limit. Suddenly, Metal Bat rushes at Garou with incredible speed. Garou still manages to avoid his attacks and attempts to counterattack, but his attacks are no longer able to faze Metal Bat either. Garou asks Metal Bat for the reason for this sudden increase in physical strength, to which he responds that it's fightin' spirit. He tells Garou to hurry up with the fight because he still needs to take care of a monster. Garou throws a manhole cover at Metal Bat, but he deflects it with his bat. However, Garou already manages to reach Metal Bat by the time he follows through. Garou suddenly launches a barrage of attacks at Metal Bat. Metal Bat tries to take the offensive, but none of his attacks connect. Garou continues to mock Metal Bat, asking him if he's going to persist until he dies. Metal Bat retorts by saying he'll fight until he wins and proceeds to initiate a killing move. To counter Garou's swift attack, Metal Bat uses his special move Killin' Moves: Savage Tornado. Unfortunately, Garou manages to repel the attack and launch a blow to Metal Bat's chest, leaving Metal Bat laying on the ground. Abruptly, someone shouts, "Big Brother!". Metal Bat is about to land a powerful blow on Garou, but stops because his sister Zenko is there. Garou then punches Metal Bat, but before they can clash again, Zenko jumps in front of Metal Bat, saying that Metal Bat made a promise not to fight while she's around. Garou gets angry, but respects their promise and leaves the fight to pursue Watchdog Man.

After Zenko explains why she's there and Metal Bat remembers the monsters, he tries to fight Elder Centipede again, but Zenko hits him in the back of the head and he falls on the floor unconscious due to his exhaustion.

Super Fight Arc
An unconscious Metal Bat is later seen being taken to the hospital with Zenko watching in worry.

Monster Association Arc
When he wakes up, he is seen watching the news about the Monster Association with Zenko. He is visibly displeased by the news. Later on, after Tatsumaki unearths the Monster Association Headquarters, they are seen watching news coverage of the event. Metal Bat discreetly throws his bag, containing his clothes and bat, out of the hospital window. A worried Zenko then asks him if the heroes will win and he reassures her saying that "Heroes never lose". He then gets out of bed, telling his sister that he is going to the bathroom, but actually goes outside to retrieve the bag, change clothes, and mobilize to combat the current threat in Z-City with the other heroes.

While heading towards the battle in Z City, Metal Bat encounters a physical anomaly, with the space in front of him appearing distorted. He decides to go around it, but the distortion turns out to be quantum stealth shield hiding a tank. He runs into King and Tareo, who are heading towards the battle, as well as Food Battler Futoshi and Waganma, who were inside the tank. Waganma asks King and Metal Bat to save Child Emperor, who rescued him. Metal Bat notes a change in the boy, but changes his mind after he tells him Narinki will foot the bill. Pineapple and Mohican come out, apologizing to him for failing to keep Narinki and Waganma safe. Metal Bat tells them to get up and encourages them to do their best. Sekingar steps out of the tank to join the heroes and children, stating that no confirmation was given on the status of the cadres, and thus King and Metal Bat will head back into battle to back up the rest of the S Class. Metal Bat compliments Sekingar, saying that he's not like the other Hero Association staff, who he believes to be helpless losers. He then fashions a slingshot using spare parts from a broken-down car, and Sekingar lasers the rope, sending Metal Bat and King flying towards the battle. They land in a bush after being caught by a Z-City batting cage net, and Metal Bat beckons King to join the battle with him.

Metal Bat appears later during the big battle between the Hero Association and Monster Association. He encounters some Black Sperm clones and asks if they know about Garou. After they attack him instead of answering, he kills all the clones. Later, he witnesses King confront multiple high-ranked monsters of the Monster Association and decides to keep a distance from him while trying to prevent any clones of Black Sperm from escaping the area.

Psychic Sisters Arc
Metal Bat briefly appears to defeat a Dragon-level threat. He is angry because he is missing his cat giving birth. He plans to take his frustrations out on the monster but said monster is destroyed by Tatsumaki and Saitama during their fight and he attempts to calm himself down afterward.

Neo Heroes Introduction Arc
After this, Metal Bat decides to quit the Hero Association and joins the Neo Heroes, who agreed to additional terms which included stationing a security guard at his home when he was away. When he visits the Neo Heroes' headquarters, he comes across Child Emperor and Superalloy Darkshine, who have also joined the Neo Heroes.

Neo Heroes Uprising Arc
Metal Bat is in attendance at the Neo Leader meeting. When Elimin and Destro arrived introduced, he questions the idea of only having two security guards at HQ.

Later, Metal Bat leads a Neo Hero team against the new monster insurrection. He easily defeats a monster on his own, admiring the power boost of the Neo Heroes Battle Suit but stating that the spikes and the electrical enhancement of his bat are not necessary. He witnesses Elimin and Destro carrying Zaedats and Infelsinave away and wonders if the security guards are the ones who saved the downed Neo Leaders.

Following the defeat of the five Dragon-level threats, Metal Bat it seen confronting Elimin and Destro, presumably asking them about Zaedats and Infelsinave. Elimin tells Metal Bat about the process of cyborgification, telling him that the Neo Heroes have been studying the process for several years. He explains that that is the reason Zaedats and Infelsinave lived, and why they were seen as "reincarnated". He then ensures Metal Bat that they will do the same to him if he ever gets gravely injured.

The two guards bring Metal Bat to their "recovery room" where people undergo the process of becoming cyborgs. Upon seeing this Metal Bat drops his suspicions. Suddenly, from behind the tanks used to hold people, Mars Leo and Solitude begin attacking him. Metal Bat asks Erimin and Destro why they are doing nothing to stop the two attackers, their response being that they want him dead. Metal Bat escapes the continuous attacks and gets up, ready to fight. However, Fuzzy stops the attack and orders Erimin and Destro to escort Mars Leo and Solitude out of the room and apologize to Metal Bat about his subordinate's behavior.

Later on, Metal Bat is seen being held in a cell in the Neo Heroes HQ. The reason for his imprisonment is explained by an official to McCoy is that Metal Bat disagrees heavily with the organization policy.