And here's another one!
The Taken Queen
(Inspired by Destiny: The Taken King, Destiny 2: Forsaken and The Callisto Protocol)
Across the city of Tokyo, whispers and rumours of an escaped lab experiment are spreading through the streets. Worse yet, sudden attacks have begun to spread across the city, with civilians randomly attacking innocents, only for both parties involved to suddenly end the fights and part ways as if nothing has happened. Something is happening in Tokyo, and no one knows what.
U.A.'s Classes 1-A and 1-B are sent to the outskirts of Tokyo, in Kijimi Ward, as part of a training exercise with a local hero agency. However, as they roam through the streets, Ochako finds a group of children huddled in an alleyway, all wearing hospital gowns, and all but one with glowing blue eyes. The one without accidently nicks her on the leg in a panic, and Ochako gets up and walks away from them.
As the next day rolls around, the heroes discover that the graveyards of Tokyo are empty. As in all the graves are empty, like the corpses had just dug themselves out and left.
Mobs begin to form in the streets. The dead seem to be walking amongst the living. The faculty of U.A. quickly recall their students to the school as the violence in Tokyo begins to escalate.
But then, it stops. The mobs go quiet.
Whatever the source of the chaos was, it is gone now.
Unbeknownst to anyone, the mobs of living and dead have moved. Tokyo has been completely abandoned. It's now a ghost town.
And meanwhile, Ochako hides away the children that she has smuggled into U.A., cutting her wrist open and allowing her blood to spill into the school's food.
Soon, similar acts of violence begin to spread across Musufatu, but at a much more accelerated rate. The dead are caught clawing their way out of their graves on CCTV, and the mobs of the living, covered in bloody wounds and bites and scratches, begin to prowl the streets in patrols and mobs, their glowing blue eyes on the prowl for anyone that they could turn to their side, hero, villain, and everyone in between.
Soon enough, the heroes that have not become part of the mobs finally understand what is happening to the people below:
They are all infected with some sort of quirk induced plague. A virus. A disease that is transmittable through transfer of blood and/or fluids. A disease that controls their movements and actions, even their minds and thoughts, though for what end no one knows.
But they are given no chance to act on this information. Ochako has infected half of U.A.'s entire populace, teacher and student, with the quirk virus. Some of those who have been infected, like Jirou and Kendo, retain their current forms and bodies, but others, like Hagakure and Mineta, are mutated by the virus into monstrous new forms, all of them turned to the will of the infected.
As U.A. falls into chaos and civil war, Izuku and those who have not been infected flee from the hordes of infected living and dead, and U.A. and its surrounding providences and wards are converted in a massive breeding ground for the virus, filled to the brim with infected. Anyone else that wasn't infected with the virus was either hunted down and turned, fled the area, or sent into hiding.
U.A. is made into the command-and-control centre for the infected, and the children are brought out of hiding and into a growing empire of their own.
It is revealed that the children are the escaped lab experiments, conducted by All for One and Doctor Ujiko to harvest their quirks and turn them into a new breed of Nomu super soldiers. What's more is that all of the children are already dead from those experiments, save for one, a small girl by the name of Keket Saisei, who's quirk allowed her to control a virus that tied everyone infected, living or dead, to her will.
And this is where we get into the specific characteristics of the virus. While the infected disease still retained some previous skills and traits from their previous lives, it was the living that were the most dangerous. Instead of taking away their free will per say, the virus actually added something to their minds: an intense, overriding loyalty to the one holding the quirk. This meant that all those infected were still of sound mind and body, but united together in spreading the virus and serving their master, regardless of all their former allegiances. This made them the most dangerous of the infected, as they could think creatively in their actions and were completely united in purpose, much unlike those that opposed them.
However, their limitations were from their master, Keket. She might have an incredibly powerful quirk at her disposal, but she is still a scared child with significant trauma from her time as a lab experiment. She had only kept the dead children around her alive to serve as her friends and had infected several people out of sheer desperation and fear once she had escaped from where she was being held. That was how this whole mess started. Now though, she's after the only thing that any child could ever want:
A home, and a family.
As the infected, now united under the banner of the Taken Queen, gather around U.A. and slowly begin to spread out from Musufatu to beyond, spreading back across Tokyo and moving onto other parts of the country, the heroes find themselves overwhelmed by one of the biggest threats that they have ever faced.
But soon a plan is formed to bring down Keket's accidental rampage across the country. Across numerous fronts, entire armies of heroes stopped retreating and stood their ground against the hordes, beginning a long series of protracted sieges that bogged down and distracted many of the Taken Queen's armies.
Meanwhile, a small strike force of heroes, accompanied by minor villains that knew the underground of Musufatu better than anyone, would sneak into U.A. and capture Keket, neutralising her and ending her hold over the hordes.
They succeed, but by a hair's thread. Almost everyone sent on the mission is infected and they sound the alarm. The only one left, Izuku, is able to grab Keket and pull her out of U.A. before the infected can get to them.
Izuku brings Keket back to the HPSC's headquarters, but soon realises that they plan to kill Keket in order to stop the virus, and the fact that they no longer have the quirkless bullets in their possession makes things even more difficult.
However, what none of them expect is for Keket's quirk to send a mental message of panic into every infected across the country, who swiftly abandon all their positions to march on the HPSC and the city around it.
With an army at their door, the HPSC accelerate their plans to kill Keket, but realising that there are too many variables that make killing her and ending the quirk virus less of a certainty and more an assumption, on top of refusing to bring about the death of a child, Izuku does his best to protect the girl as the infected break down the walls of the city and surge forwards, overrunning the heroes' defences and bringing even more into the fold, with the infected Ochako, now called the Taken Daughter, leading the charge.
With almost all his friends now infected, and the rest falling one by one, Izuku pleads with Keket to stop this, stop this madness before everything falls.
But Keket cannot hear him. She simply stares out to the chaos and fire below, seeing all the death and destruction that has been carried out in her name.
She can't release the people that have been infected with her quirk. She doesn't know how, and there isn't enough time to teach her.
There's only one way now.
She takes a knife into her hand and slices her own throat.
Thanking Izuku for showing her kindness, Keket throws herself off of the HPSC building and onto the ground, killing herself. As the life leaves her, so does her quirk from the millions of infected, and one by one, her unwilling hold on them releases.
But they still gather and mourn for her regardless, listening to her last words and comforting her as she dies. Ochako holds her hand even as her mind is freed, and as she finally passes, she and those that once belonged to her hordes carry her away to be buried.
As the dead, before and recently passed, are collected and buried once more, the last of those still feeling the effects of Keket's quirk gather for her funeral, burying her not too far from U.A. before the last of Keket's quirk passes from them and they all go their separate ways.
Japan and U.A. would begin to rebuild from the chaos, but everyone would be shaken from it. Those that had been overwhelmed by the Taken Queen's virus still hear the whispers of the quirk from time to time, and those who weren't are plagued by nightmares of their allies attacking them and trying to spread the virus to them. An uneasy period of rebuilding takes place through a shaken Japan, and the public is left to mourn their losses and try to find themselves once more in a world that suddenly doesn't make sense.
And deep in the labs, Doctor Ujiko would mourn the fact that he had been unable to harvest Keket's quirk for his experiments and his master's use before she escaped - an unforeseen development - but does not mourn for long. Shigiraki's power is already growing with each passing day. Soon that old quirk won't matter at all...