Final War

The Final War is the final confrontation between the Heroes and the Villains to determine the fate of the world.

Prologue
With Tomura Shigaraki's impending completion as the All For One Quirk accumulates into his body, All For One prepares to finally pull the trigger on the plan to steal One For All from Izuku Midoriya, thus giving them the power necessary to finally assume world domination. The first step being to make use of Class 1-A student Yuga Aoyama, his secret mole, to lure Izuku to a disclosed location so that he may be ambushed.

Yuga's ploy is discovered by Izuku and he is captured and interrogated by the Heroes and his classmates. Realizing he is a victim forced against his will into fulfilling All For One's orders, Izuku suggests that they can use Yuga's connection to All For One in order to lure the Villain out of hiding. This leads Eraser Head into coming up with an idea that can make use of this connection, and give them the chance to fight the Villains on their own terms, defeating them all once and for all.

The Plan
The first part of Eraser Head's plan involves luring All For One to a specific location, making Yuga appear to betray Izuku as bait. The Heroes determine that All For One possesses some ability that allows him to detect lies from individuals, even through voice, and figure they need to work around this so that he doesn't suspect Yuga or his parents of fowl play. Eraser Head decides to employ his protege, Hitoshi Shinso, as through training he has allowed his Brainwashing Quirk to let him order his brainwashed victims to speak, and use this ability on the Aoyamas to allow them to speak with All For One without him able to detect any malicious intent.

The second part of the plan is devised by the "Counter-Force" team, led by All Might, which is to split the Villains up divide-and-conquer style so that they are unable to cooperate amongst themselves. This phase is achievable thanks to Eraser Head's suggestion of using Neito Monoma to Copy the contained Kurogiri's Warp Gate Quirk, giving the Heroes the ability to create numerous portals to anywhere in Japan which the Villains can be teleported to. This also allows the Heroes to catch All For One off guard after they successfully lure him out of hiding, knowing that he can use the Search Quirk to determine their locations.

U.A. High School
In order to detain Tomura Shigaraki, deemed the most dangerous threat by far of the Villains, the Heroes decide to transform the already fortified U.A. High into a floating Fortress, also known as a "Coffin in the Sky", to keep him encased within. Thanks to the ingenuity of Mei Hatsume and the Development Course, they design the structure to combat Tomura's Decay, as the effected pieces are ejected which would allow them to Decay safely in the air. Repairs would also be done on the fly by the Development Course and various U.A. staff and students maintaining the structure, with additional supplies provided by Momo Yaoyorozu. A team of electric users also not only provide the power to keep the building running, but also to encase the fortress in an electric barrier, preventing Tomura from escaping.

For further reassurance, Eraser Head and Neito copying the Erasure Quirk will provide backup to erase Tomura's Quirks. All this to allow Izuku to fight Tomura face-to-face, backed up by a team of Heroes led by Best Jeanist.

Gunga Mountain Villa
To deal with All For One, the next biggest threat, his location is chosen to be the ruins of the former Gunga Mountain Villa. As the Number 1 Hero, and potentially the strongest remaining Hero left, Endeavor is selected to face down All For One, backed up by Hawks. Their plan is to keep All For One in the air, and to keep the fighting to between just the three of them, to prevent him from stealing any other Quirks, with the primarily goal to destroy his life support system.

They are further backed up by a group of Heroes and U.A. students who will deal with any of the leftover villains that end up accompanying them on the ground.

Kamino, Yokohama
They decide to send Dabi to Kamino, the site of All Might's battle with All For One, with Shoto Todoroki volunteering as the one to personally deal with his brother, at his father's behest. The Flaming Sidekickers are assigned to assist him in dealing with the Blueflame user, with several more Heroes set to deal with any accompanying threats.

Okuto Island
To handle Himiko Toga and her penchant for escaping, the Heroes choose Okuto Island, specifically the Okuto Aquarium controlled by Gang Orca, in order to isolate her, unable to flee. Due to having the most experience in dealing with her, Ochaco Uraraka and Tsuyu Asui are set to be the ones to personally confront Himiko.

Central Hospital
The Heroes learn that Spinner is leading an army of heteromorphs, consisting of members of the Paranormal Liberation Front and civilians who support their plight, in order to storm Central Hospital and free Kurogiri, having figured out it is his location despite their attempts to spread false rumors. Present Mic takes the lead to defend his friend accompanied by the remaining available Heroes and Police Force, as well as 1-A students Mezo Shoji and Koji Koda, who volunteer due to their connection to the issue.

Jaku City
Aware of the Villains underestimating the Heroes' available numbers, and knowing alongside Kurogiri, they will also attempt to reclaim Gigantomachia, another team is sent to the ruins of Jaku City, to protect the containment facility built to hold the unconscious beast, still there after his rampage in the War.