Who's this Dekiru and why do all the Pros want to adopt him?

Grief

Izuku was woken up by the smell of fast food katsudon. His mom buys katsudon from the place down the road when she wants to get him a treat but didn't have the time to make it herself.

He rolled off of the couch with a dull thud. "Hey mom," he said, rubbing his eyes. Then he froze, as he saw Keigo standing in the kitchen.

That's right. His mom was gone. She would never make him katsudon ever again, they would never laugh over cartoons on the rare Sunday mornings she didn't have work, they would never go to the mall again where he would excitedly drag his mom from hero store to hero store while she patiently listened to him. He wouldn't even be able to go visit her in the hospital, where they would have long winding talks about anything and everything until he had to go to work.

She really was gone.

"Fledgling?" Keigo asked, and when did he move to stand in front of Izuku? "What's wrong?"

"I'm not hungry," he said quickly, fleeing to his bedroom. He's pretty sure the door plate fell to the ground from how hard he slammed his door.

His lungs burned as he gasped for breath like a drowning man, sliding down to sit next to the door. He was shaking as a weight pressed down on his chest, his head filling with fogs.

He hasn't been in his bedroom since yesterday, having fallen asleep on the couch while working. The stares of All Might plastered on every poster, bobble head, pillow burned his skin, silently mocking him for thinking he was allowed to have anything.

Burden.

Quirkless.

Pathetic.

You killed her.

Burden.

Quirkless freak.

Sniveling coward.

You killed her.

Burden.

Quirkless scum.

Take a swan dive off the roof and hope for a quirk in your next life.

You killed her.

"Kid- fledg- to me-" the words were choppy as red filled his vision. "Need you- breathe-"

A pattern was being tapped onto the back of his hand, and he tried to follow in stuttering breaths. In, and out. In, and out. In, and out. Eventually, the weight on his chest let up enough so that he could finally breathe.

Awareness trickled back to him slowly. He was sitting with his back to the wall next to his door, his knees tucked to his chest. His face was tear stained, he could already feel his eyes getting puffy. One hand was clutching his chest while the other was being held by Keigo, who was kneeling in front of him. His wings were spread out around him, blocking Izuku's view of the room.

"You back with me, fledgling?" The hero asked, still rubbing gentle circles into the back of his hand. Izuku nodded shakily. "Can you tell me what happened?"

"My mom," he stuttered out. "She always got katsudon from the same place after work. And then- And she's not here. And then I came in- and- all I could see was All Might and- and I could hear the voices. Calling me a burden, quirkless freak, pathetic coward-"

"Izuku," Keigo's voice cut through, and he grabbed Izuku's hands, pulling them to his lap and away from the hair they were pulling.

"I'm fine," Izuku responded instinctively.

Keigo sighed, then picked up Izuku like he was a couple of grapes, his wings continuing to block Izuku's view until they made it to the living room. He was dumped onto the couch, and Sushi climbed onto his lap with a needy meow.