Chapter 1 — Sinister Origin

Four-year-old Izuku really wants to learn what Quirk he has, because he really wants to be a hero when he becomes older. The doctor, however, replies that he only seems to have a relatively powerful regeneration Quirk that prevents him from becoming sick, and tells him to give up on his dream. However, that night, Inko tells him that he can still be a hero.
Ten years later, though, life only seems to be bent on keeping Izuku downtrodden: he's been bullied on a daily basis by his former friend Bakugo and all his classmates, with even his teachers being complicit in the abuse, with only his mother still being on his side.

During a camping trip with his classmates, Izuku ends up picked for the "spend the night along in the woods" test (which has happened multiple times already) just on the night he becomes fourteen. He wishes his Quirk - which manifests in the form of small micro-organisms in his blood - could do more than just keeping him healthy.

His musings are interrupted when he hears someone running nearby, with a car roaring right behind. Izuku rushes to the source, and sees a girl he attempts to guide to safety, only for the car driver to pull out a gun and shoot. Izuku attempts to shield the girl, but the bullets pierce through him and fatally injure the girl, who is then killed when the driver empties a gun clip on her.

While regenerating from the bullet injuries, Izuku attempts to get the girl to safety and calls first emergencies and then his teacher, but both prove unwilling to help, and Izuku tries to call his mother before resorting to the wild idea of trying to use his Quirk to keep the girl alive - but he's unable to revive her.

Hours later, Inko finally manages to arrive to the camp, where the police are starting to investigate what happened, only to find a distraught Izuku who thinks he's cursed: the girl has somehow revived as a zombie-like creature. A cop gets startled when the girl makes a sudden move and shoots at her, and Izuku discovers he can give orders to the girl.

Back into the city, Inko worriedly admonishes her son for acting as a bullet shield, but Izuku is more saddened by the fact that he could not actually stop the bullets. The local chief of police comes and tells them the girl is Tae Yamada, who was reportedly disowned by her parents after running away with her boyfriend, although the chief suspects that Tae (who is Quirkless) was actually sold out to a traffic ring that used her as a sex slave. In short order, the Midoriyas find themselves having Tae living with them.

Tropes That Appear In This Chapter:

A Birthday, Not a Break: The day Izuku finds out his blood can also create zombies is also his fourteenth birthday.
Adults Are Useless: When Tae gets fatally shot, Izuku tries phoning an ambulance, but the emergencies' caller thinks he's just a kid who woke from a nightmare and hangs up, leaving him to fruitlessly try to handle the situation on his own. He then tries calling his teacher, who is too drunk to be of any use.
Be Careful What You Wish For: Izuku openly muses that he wished that the microorganisms in his blood could be used externally so that he would be more useful to others. He then gets his wish by trying to use his blood to cure a girl who was fatally shot after attempting to call for help fails. It worked... sort of.
I'm sorry mom... I... I think my Quirk makes... zombies.
Foreshadowing: There are several instances of people making comments about mutant-type Quirks in a negative manner, hinting at the Quirkist "hierarchy" that gets more detailed in later chapters.
Godzilla Threshold: When it appears no one is willing to help Izuku, he decides to use his blood in a desperate attempt to see if it will do anything.
Humble Hero: The first instance of Izuku practicing true heroics (as well as surviving a lethal incident) is when he saves a girl from a mugger when he was twelve, getting stabbed seven times for his troubles. He never learned who she was and didn't see her again, but he doesn't care as long as she was okay.
I Love the Dead: The police officer feels compelled to remind Izuku that necrophilia is illegal when they tell him that he basically has custody of the zombified Tae.
In Spite of a Nail: While in canon Bakugo becomes a bully to Izuku because he's Quirkless and therefore is "too weak" to be a hero, here he remains an abusive prick, this time because he thinks his quirk is a Useless Superpower and later claims that it makes for more of a villain's quirk.
My God, What Have I Done?: By the time Inko gets to Izuku, he ponders if he's "cursed" when his attempts to heal Tae turned her into a zombie.
Right for the Wrong Reasons: Izuku's doctor reasons that he should give up on being a hero because his quirk isn't geared for that kind of work, being able to stop a bullet being one example he gives. Ten years later, he tries jumping in front of a gun to save someone, only for the bullet to pass right through him and hit the victim anyway.
Izuku: Now we know bullet's can't kill me... too bad my body didn't shield her though...
What Kind of Lame Power Is Heart, Anyway?: While Izuku has a quirk in this version, his doctor still tries deterring his dream of being a hero because (on its face) his Quirk is useless in that line of work, encouraging him to look for a more "appropriate" career paths like in medicine or experimentation.