I changed one small thing with his quirk and that is that any event/experience that causes him to feel sad is what makes his wings bigger.

Izukus pov:
"MUM! MUM!" (Yes I'm British) "Wake up! It's time for my quirk to come!
Inko:"ok ok just a second izu and be a bit more quiet so you don't wake up your father also you need to eat before we go to the quirk doctor."
Izuku:*whines* "fiiiiiine!"

15 minutes later

Inko: "Izuku calm down! I knew I shouldn't have given you coco pops"

Doctor walks in

Doctor: "well I'm glad to say that little Izuku does have a quirk but its a bit of a dark one. But before I explain it should manifest in
3
2
1"
And suddenly a ripping noise was heard by everyone in the room and two small black wings popped out of his back.
Izuku: "what are these?!"
Doctor: "that is your quirk, it's called....
....Despair wings"
Izuku and inko shivered when they heard the name.
Inko: "w-why is it called something so sad and depressing?!"
Doctor: "well because it is sad and depressing. Izukus quirk manifests in the form of two small wings that grow whenever he has a bad experience. The amount of growth the wings go through is dependent on how bad the experience was. For example if he gets a bad score on a test it'll grow by about 1 feather on each side. But if let's say that someone close to him dies, then his wings will increase by about 20 feathers.I also suspect that he'll gain abilities and techniques from the experiences as well."
Inko was shocked that her son had such a depressing quirk and worried about him
Izuku in the other hand didn't care massively and was just flapping his tiny wings experimentally.
Inko: "W-well thank you doctor I think we'll go home now. Come along izu."
Izuku: "Hai!"
On the way home inko was muttering to herself saying things like "he will put him through hell." and "we need to escape." Izuku was worried about his mother and asked "mum is everything ok?" And she responded "yes sweetie everything is fine we are just going to go on a little holiday!" That got Izuku excited.

Inko had decided to take Izuku to the park so she could clear her mind and after a whole day of playing at the park with Bakugo Katsuki she brought Izuku home. Another reason while inko spent the whole day there was because she was waiting for her husband hizashi (dragon) to go on patrol so when she thought he was out she went back home with Izuku to collect their things. She opened the door and...

HE

WAS

THERE

Hisashi: "aah inko how nice of you to finally come home." He said while smirking in his usual sadistic way. "Hey izu would you come here for a second" he said still smiling that awful smile "now I just need you to look at your mother, can you do that for me?"
Izuku: (oblivious) "Hai!"
Hisashi: "good ,you look very pretty today Izuku." He said his grin getting even wider as he saw inkos look of horror.

Inko: "you wouldn't dare!" Inko shouted.

Hizashi: "you really think so? Oh and by the way did you know that when a child gets their quirk they always send a letter back with aaallll the details. Like how certain events will cause a rise in power."

Inkos face turned very pale and stared at hizashi, then izuku

Hisashi: "now izuku still watching mummy?"

Izuku: (still blissfully oblivious of what's going on) "Hai Dad!"

Hisashi: "good now look at this." He says as he shoots a massive fireball at his wife.
Inko started screaming as she burnt alive in front of izukus face (ps if you wonder why none of the neighbours hear it's because abuse is common in the house so hizashi sound proofed the walls) inko fell to the ground, crawling towards izuku as he looked on in horror and she let out a final cry of "i-zuku" and then

Smash!

Hisashi had stomped on her head crushing it
*Izuku started puking* "CRAP LOOK WHAT YOU DID YOU LITTLE SHIT!! YOU PUKED ALL OVER THE CARPET AND MY SHOE!!!
CLEAN IT UP BEFORE I BEAT YOU OR WOULD YOU LIKE ME TO RAPE YOU?!?!"

Izuku couldn't respond since he had passed out

Hisashi: "huh I guess it's the latter for you" as he drags izuku to his room.....

Hey I hope you guys liked that (even though some shit went down) and also this is my first story so any feedback will be appreciated Ember out!