An AU where Deku has either a younger brother or older brother or a sibling. That sibling has the ability to control external fire, a combination of his father's and mother's quirks. Does this have the potential of a quirkless Villain Deku?
*flashbacks of twin AUs from KHR*
Oh boy. Uh. This idea has potential, that’s certain! But if I’m being honest, I wouldn’t read it if it’s centered around Deku developing jealousy/hatred for this sibling that has a combination of their parents’ quirks, or if (ESPECIALLY if) it’s centered around this sibling being abusive to him while being the “star child.” (… Holy shit. That’s Katsuki. THAT’S KATSUKI, WHAT THE HELL, KHR BAD!TWIN FICS ARE LITERALLY THE RELATIONSHIP BETWEEN IZUKU AND KATSUKI? WHAT.)
… Anyway. Yeah, I’m a bit tired of the abusive-sibling-relationship trope.
However! If it went in the direction of, say, the two of them working together? Maybe with the sibling being protective of Izuku because he doesn’t have a quirk? And Izuku, who doesn’t want to be a burden (or in the case of him being the older sibling, feeling inadequate because he is the older sibling but it’s the younger one doing the protecting) ends up encountering All for One?
Maybe he’s found by AFO. Maybe he and his sibling are attacked by a villain, with his sibling being greatly injured in the aftermath. Maybe he is scared, terrified, and oh, so angry at himself for having been unable to protect his sibling.
But, then, a man comes by. Izuku instinctively curls around the unconscious, battered form of his sibling, glaring at the man, because - because what if he wants to hurt them? Hurt his sibling? They aren’t awake, they’re hurt, and Izuku… He’s the older brother. He’s always been the one protected, so the least he can do is shield his younger sibling with his body.
The man takes a few steps towards them, and Izuku, tears in his eyes and shivering, holds his sibling closer. The man stops a few steps away, looming over them, and Izuku is afraid, absolutely terrified of what this man might do to him, do to his sibling.
But he doesn’t flinch away. He bares his teeth as a cornered animal may, tucks his unconscious sibling closer to his chest, trying to hide as much of them from sight as he can. He can’t see the man’s face, as it is obscured by some mechanism. But he can feel a weighted gaze on him, the man observing, sensing him, through the mask.
“… You are powerless.”
Izuku refuses to look away. He tucks his sibling further behind him, and stiffens at the rough laugh the man releases.
“Interesting. Powerless, yet you still fight. Disgustingly like him, and yet… Not.”
The man kneels, expression unseen. He holds out his hand and speaks.
“I shall give you the power you seek.”
… So, maybe both Izuku and Ambiguous Sibling become villains this way. Are taken under AFO’s wing, trained, etc.; Izuku is happy that he is useful and can protect his sibling and his sibling is happy for him - they can protect each other now, they have each other’s backs.
At some point, AFO reveals (or maybe, they find out through other means) that he isn’t exactly a stellar citizen. Nope. He’s technically a villain. Technically, the biggest, baddest villain. Izuku is conflicted as heck, because he admires All Might, and always wanted (still wants?) to be a hero. Maybe the sibling doesn’t mind. Maybe the sibling never really cared about heroes or villains, as long as their mother and brother were alive and happy. Where Izuku goes, they go. So it’s Izuku’s decision - what to do?
From here, maybe they both become not-quite villains the border on vigilantism, or maybe they end up joining AFO and Ambiguous Sibling decides to go into the hero course while Izuku handles things as AFO’s successor. Following the latter idea, the sibling manages to layout the foundations of their infiltration in the hero society, and Izuku follows him eventually - whether that involves both of them enrolling at Yuuei, or simply being in the good graces of the well-known heroes.
Their goal? Who knows. Maybe Izuku’s goal is to somehow resolve the feud between All Might and AFO - because, he still admires All Might, but respects AFO/owes him for giving them this chance. Maybe Izuku wants to find a balance in society, where a symbol of peace isn’t necessary.
Maybe his goal is to dismantle the hero system altogether. (That sounds pretty villainous, right? Because, why dismantle the hero system? Why remove the peace? Who would want to remove the system other than a villain?) But no. He doesn’t want to dismantle it for some nefarious purpose - in fact, all he wants is to remove it’s necessity. He doesn’t want to remove the society entirely - it’s far too important, what with quirks being a factor - but, if people could come to terms with each other, if they could set their differences aside, to not use their quirks to harm…
AFO, after some discussion, thinks about it. He thinks, considers. And eventually, he agrees, relents, and puts his faith in Izuku.
(Because AFO, Sensei, isn’t the epitome of evil. His actions in the past were nefarious, he is no shining example of virtue. But he is still a man. A man far past his expiration, that seeks vengeance and his own brand of justice, two qualities which label him a villain. A man who wants to see the fall of All Might, a man who would settle for removing All Might from his spotlight in the eyes of the people. A man who is old, tired, and has, admittedly, grown fond of the two Midoriyas. And he wants to see an end to his goal.)
((Oooorrr maybe that’s just what he says to manipulate Izuku and his sibling, I don’t know, who the fuck knows what’s going through this man’s head other than Horikoshi))
There are those who oppose this, oppose Izuku’s dream. He’s young, he’s idealistic, he doesn’t know what he’s talking about. He spouts peace and ideals and justice, and he isn’t willing to bloody his hands for it? “Hah!” Heroes are needed, because there will always be some selfish villain that wants to take matters into their own hands. No one believes him, and it takes him declaring war on the heroes (the system) for them to take him seriously.
But hey, if that means becoming a villain to accomplish his goal, then so be it.
why did I write all of this
*coughs* So yeah, it does have potential to be a Villain!Deku AU! I couldn’t really think of anything for *Quirkless* Villain though - Izuku isn’t spiteful/jealous enough to become a villain purely because his sibling has quirks, imo. And quirkless, I don’t feel he’d get very far as a villain - he might be resourceful, but that can only get him so far.
Unless you mean he becomes, like, the standard evil mastermind villain that is ALL brainpower/machinery/weaponry and no inherent magic abilities. Oh my god that’s some funny imagery