Gigantomachia/Synopsis

History
Gigantomachia was a member of the League of Villains before even Tomura Shigaraki was. He once served as All For One's bodyguard during his reign of terror, although it is unknown for how long. Thanks to his Endurance Quirk, he and Doctor Kyudai Garaki discovered him capable of possessing multiple Quirks without significantly straining his body, so equipped a variety of abilities that together would make him the perfect, unstoppable bodyguard, resulting in seven Quirks total.

Foreseeing his inevitable downfall, All For One decided to hide Gigantomachia in the mountains, using his Mole Quirk that he had provided him. After his injury by All Might's hands, he had the Doctor and Machia find Quirks to help obtain him back to full health. He also advised Kurogiri to use Machia once he believes to no longer be capable of ensuring Tomura's safety.

Months before the start of the U.A. High School Entrance Exams, Gigantomachia was walking through the city towards the Springer's Hero Office, but he got lost. He threateningly asked two middle-school girls for its location, but the girls were too terrified to utter anything. Gigantomachia took their silence as offensive and put his hand on a building, which caused the building to start breaking down.

Suddenly, Mina Ashido jumped in and made up some directions. Gigantomachia thanked Mina as he wandered off while rambling about everything he does is for his master.

Vs. Hero Killer Arc
Alone in the woods, Gigantomachia listens to a radio report about Stain's defeat.

Shie Hassaikai Arc
After All For One's defeat, Kurogiri informs Tomura about the "power" All For One left behind and wondering if he should retrieve it to advance the League of Villains.

Kurogiri began searching for Gigantomachia in the mountains. However, Gran Torino and Naomasa Tsukauchi managed to track down and find Kurogiri with the help of eyewitness reports and have subdued him. Kurogiri asks Gran Torino if he knows of the rumors about a "ruffian" appearing on the mountain where they are at and the reason he is here is to speak to the "ruffian". Gran Torino would prefer Kurogiri to tell him all about it behind bars. Suddenly, a huge noise reverberates in the area which catches Gran Torino's attention, and Gigantomachia makes an appearance.

Gran Torino and Naomasa are seriously injured and the task force suffers severe casualties at the hands of Gigantomachia, but they manage to take Kurogiri into police custody, at the cost of allowing Gigantomachia to escape, after having completely destroyed a large portion of the mountain. Later, Gran Torino phones All Might to inform him that they captured Kurogiri, and also to warn him about the threat posed by Gigantomachia, which he defines as a walking disaster.

Meta Liberation Army Arc
Sometime between late September and early October, before the Hero Billboard Chart JP, Gigantomachia finally meets Tomura and the new League of Villains. Tomura expresses glee as he realizes that Gigantomachia must be the power Kurogiri mentioned to him. Dabi and Mr. Compress are stunned by his appearance.

After setting down his radio and confirming Tomura's identity, Gigantomachia challenges the League to see whether they are worthy of his loyalty. Gigantomachia easily prevails over the League managing to incapacitate Himiko Toga, Twice, and Mr. Compress.

He is dismayed at their performance, tearfully crying out that Tomura is too weak to be a successor, calling the League unacceptable while questioning All For One's motives. He comments that he wants to accept Tomura but can't. A tearful Gigantomachia proceeds to smash the ground, causing all League members to lose their footing. Gigantomachia's sheer power ends up destroying the majority of the landscape.

During the confrontation, Kyudai Garaki speaks to Tomura through the Gigantomachia's radio, regarding his uncertainty in the League's current state and the need for help. Kyudai explains that Gigantomachia has unlimited stamina and did not require any modifications to serve All For One as bodyguard and confidant. He reveals that All For One hid him to make sure his legacy would live on through Tomura's command.

Dabi questions his usefulness, with the Doctor proclaiming that Gigantomachia is loyal to a fault, so he's in despair when faced with Tomura in comparison. Dabi shoots a wave of fire toward the giant brute, but he simply charges straight through it, completely unaffected by it.

Before Gigantomachia continues his attacks, a voice recording of All For One plays from the radio. It effectively calms Gigantomachia as he nuzzles and purrs at the radio. An irritated Tomura states that he does not want Gigantomachia. The Doctor responds with Gigantomachia can be useful and warps the League to a secret laboratory filled with multiple Nomus to continue the conversation.

After their conversation, Kyudai instructs Tomura to get Gigantomachia to submit. Kyudai has the League, minus Dabi, warped back. A confident Tomura tells Gigantomachia that the 'future king has returned'. An amused Gigantomachia replies that a king should "inspire dread, be admired, and be strong".

The fight continues and goes on for weeks. While he fights the other members, he ignores them and mostly focused on fighting Tomura who still possessed a stronger resolve. Gigantomachia calls his efforts weak but isimpressed by his determination. Gigantomachia would fight and go to sleep while the cycle continues.

During one of their breaks, Re-Destro, supreme commander of the Meta Liberation Army, contacts the League and challenges them to confront their organization, under the menace of revealing their position to the heroes if they refuse. Tomura accepts the challenge and decides to take advantage of it to kill two birds with one stone: He plans to use Gigantomachia against the Meta Liberation Army. Gigantomachia will inevitably crush Re-Destro's army, but will be weakened enough so he can defeat him and subdue him to his will.

Kyudai warps the League to Deika City, where they face off against the Meta Liberation Army in an event known as the Revival Celebration. Throughout the battle, they are aware of the time until Gigantomachia awakens, however the MLA is stronger than expected and they take chances of being defeated before this happens.

Doctor Garaki, who has been listening in on the fight, notes that it would be sad for All For One for his protege die here, so he uses another record of All For One to prematurely awaken Gigantomachia and orders him to the League's location. Gigantomachia erupts from the ground, and when he notices that the League was gone, he uses his nose, he tracks them down after catching Tomura's scent.

Gigantomachia arrives and runs through the city, while easily sweeping aside everything and everyone in his path. While closing in on Tomura's location, Gigantomachia is nearly impeded by Geten with the ice user's Quirk. However, he easily swats the latter away and continues on his path. Gigantomachia finally reaches Tomura's location but stops once he sees Tomura embracing his true evil.

After half of Deika City is turned into a barren wasteland by Tomura's awakened Decay Quirk, Gigantomachia can only look in awe while he witnesses Tomura emerge victorious over Re-Destro who concedes defeat and control of his army to Tomura. As he looks at the sight, Gigantomachia mentally compares the proud Tomura to All For One and sheds a tear of joy at seeing Tomura truly being his master's successor.

Sometime later, Gigantomachia is at the ceremony Re-Destro holds in honor of Tomura. While in the audience, he bears witness to the creation of the Paranormal Liberation Front that will be merged from the League and the Army.

Endeavor Agency Arc
After the organization's formation, Gigantomachia and his allies are present at a meeting in which Hawks informs them of Endeavor's decision to take on two new interns, as well as their following conversation about how Tomura is about to undergo surgery to obtain ultimate power, and that once he does, everything will be in their hands.

Paranormal Liberation War Arc
Thanks to Hawks being an undercover agent for the Hero Public Safety Commission, the Heroes plan an all-out assault on the Paranormal Liberation Front by the end of March, before Tomura's procedure is completed. When the raid commenced, Gigantomachia was sitting in the underground bunker, holding the radio in his hands, waiting for his master's orders. When Tsukuyomi unleashed his Dark Shadow's Ragnarök, Gigantomachia didn't react to it at all, but Dark Shadow still recognized him as a "real monster". As the fight continued, he still blankly looked at the radio.

Even despite Mirko and Present Mic breaking his vat, Tomura was awakened. Gigantomachia then picked up his master's scent and stood up. Tomura then started decaying the area around him and after he finished, he picked up Kyudai's phone and ordered Gigantomachia to rally the League's members and bring them to him, to which he replied with an enthusiastic roaring. He then increased in size and broke through the villa's floor, coming to the battlefield for the first time since the raid started.

He soon picks up some the core League of Villain members, with Dabi bringing Skeptic along for the ride, putting them safely on his back and begins to head towards Tomura's location in Jaku City. However, he was stopped by Mt. Lady, who swore she wouldn't let the giant pass. He completely ignored her presence, slowly pushing forward until he chose to change directions to the shortest route to Jaku, so he grabbed her leg and threw her away. He continues to rush forward as several Heroes try to keep up and attack him, but are blasted away by the League on his back.

He soon finds himself slowed down as Mt. Lady and Kamui Woods entangle themselves to Gigantomachia's leg, refusing to give up. He then finds himself thrown into a trap set up by the remaining U.A. students in the area, sinking him into the ground with the intention of throwing a sedative into his mouth, hoping to put him to sleep. Several students try to forcefully pry his mouth open, while the others attempt to attack the League on his back. They manage to get it open and start to throw their vials in, but he simply blows them all away, sending everyone backward.

Dabi proceeds to shoot his fire, burning up the area and preventing them from getting close. But before Machia can resume his rampage, he once again falls into another trap as the explosives beneath give in, sinking him back down into the ground. Just then Mt. Lady returns, jumping on his back and forcing his mouth open, figuring out the student's plan. Thanks to her Acidman, Mina is able to emerge from the fire unharmed, and prepares to throw the sedative into the beast's mouth.

Gigantomachia annoyingly proclaims there is no need to waste time on flies, as he decides to shake the heroes off so they can't regroup. He tosses Mt. Lady away and knocks her out. He tries to grab Mina, though suddenly, Eijiro Kirishima intervenes and saves her from being crushed by his giant left hand. The giant stands up, and grabs his master's comrades, saving them from falling to the forest floor.

All of a sudden, Eijiro climbs up the giant's leg, and while his first canister is shattered by Himiko's knife, he directly throws Mina's canister toward the mouth, successfully inserting it in. The giant tries to swat at him, but he is saved just as the U.A. students open fire on Gigantomachia with cannons. Majestic, Fat Gum, and the other Pro Heroes move in on his location, prepared to finish the job themselves. Gigantomachia is irritated, proclaiming that the flies are never-ending, as his lower canine jaw begins to move on his eyes, as he undergoes a transformation.

Unleashing the full power of his Mole Quirk, Gigantomachia had absolutely decimated all the Heroes in his path, severely injuring and killing some of them, with the U.A. students only barely surviving due to Majestic's interference. Machia continued for a complete straight line toward Jaku City, destroying everything in his path and leaving behind a trail of destruction.

In a few moments, he's already in Sairo City. As he's rampaging through the buildings as if nothing's there, he suddenly notices how he can sense two of his master's scents. The remaining Heroes try to mobilize to deal with the beast, with some assisting in evacuating, while some warning the Heroes fighting Tomura of his impending arrival. Soon enough, Gigantomachia finally reaches his master's location. Shoto and Nejire Chan unleash their powerful Ultimate Moves on Tomura, attempting to finish him off, but the giant interrupts them and saves Tomura from certain death.

He transforms back into his normal state, asking for a command, and putting his master on his back, hoping that his comrades could awaken the unresponding Tomura. As Gigantomachia awaits for orders, suddenly wires from the sky wrap around the battlefield, as Best Jeanist descends from the sky. The hero restrains Gigantomachia and the League, while Spinner and Compress wonder how could Gigantomachia be pinned down so easily, and Spinner realizes that Machia had finally gotten out of breath upon stopping his rampage, and Tomura must give an order for him to act again. Tomura manages to briefly wake up, ordering the giant to "destroy", prompting his Endurance to reinvigorate himself as he starts to break free from the wires.

As the giant struggles, Best Jeanist attempts to hold him back, but finds trouble due to the interference of Near High-End Nomu also summoned to the battlefield. Eventually, the wires start breaking and he manages to break free, only to have Endeavor fly up to his face and attack him as his last effort, as he knocks himself out by doing it. Gigantomachia falls on the ground and suddenly starts losing all of his strength, as the students' anesthetic has started working. Unable to do anything, the behemoth lies on the ground, as more fibers start restraining his movements once again.

With Gigantomachia unconscious, Compress and Spinner do a last ditch effort to wake up Tomura so they can make an escape. This succeeds, however Tomura is now possessed by All For One, who uses his Quirks to command the Near High-End Nomu to let them escape. Spinner questions leaving Gigantomachia behind, but All For One says that Tomura must deal with his losses, all for his sake. The remaining Villains then succeed in escaping.

After the war concluded, Gigantomachia was successfully captured and detained by the heroes, with his transportation to Tartarus prison being planned. One guard questions why they couldn't just kill the behemoth and the other guard responds by saying that bullets would just bounce off him and using missiles to execute him would be considered unethical as he is still a human. The giant's planned transport however was cut short by the prison break caused by "Tomura" and the Near High-Ends. Instead, a large containment facility was built around the beast.

Final War Arc
Within a month after the Paranormal Liberation War, the Heroes prepare for the Final War against the army of villains led by All For One. Majority of the Heroes plan to take part in an operation that will divide and conquer All For One's forces, splitting them up all over Japan and dealing with them individually. While that is going on, a group of Heroes led by Mt. Lady is assigned to Jaku City, where Gigantomachia's containment facility is, in order to protect him from the remnants of the Paranormal Liberation Front that look to free him.

At some point during the battle at the Jaku Hospital containment unit, the anesthesia that U.A. students used to throw into Gigantomachia’s mouth wore off, allowing Gigantomachia to finally be awakened. Before the behemoth can go on a rampage again, Hitoshi Shinso was able to use his Quirk to brainwash the villain into submission using Persona Chords, imitating All For One’s voice after using the recording device from Yuga Aoyama’s phone.

With Gigantomachia now under complete control, the behemoth gathers the remaining heroes and streaks across the landscape to the Gunga Mountains where the U.A students join the battle against All For One as reinforcements for the Heroes and payback for the Paranormal Liberation War. When Gigantomachia arrived at the Gunga Mountains, Hitoshi brainwashes the behemoth to attack All For One by throwing a giant mountain boulder directly at his master, much to his surprise. All For One was infuriated, cursing out the insects who were on Gigantomachia's back, Eijiro and Hitoshi.