A Hero's Dirty Work (Villain Deku / Vigilante Deku au)

Preparations

Midoriya immediately turned to Eri as soon as Dabi was gone. "Why didn't you tell me you started your training already?" he asked her. He couldn't help the hint of betrayal in his voice. Did she not trust him?

She looked down at the ground, fiddling with her hands nervously. "I didn't want you to worry," she said meekly. "The only person that can train me is him, and I know you didn't want him to be near me."

Midoriya took a deep breath. "Yeah, I sure didn't. That's alright, though, because now we have Twice! Say hi to Eri, Twice!"

"Hello Eri! Hi, Eri!" Twice said. Midoriya cocked his head to the side, and Twice froze.

"I guess that doesn't happen very often?" Midoriya ventured. Twice nodded slowly. "Well, this is a lot easier if both of your personalities already like her."

"Is mister Twice okay?" Eri asked, sounding concerned. Midoriya nodded patting her head comfortingly and smiling. He didn't honestly know if he was trying to comfort her or himself, but it didn't really matter.

"He's alright, don't worry. Something happened a long time ago that makes him feel like two people, and he's just surprised because they don't usually agree on anything," he told her.

"What did they agree about?" she asked curiously, her eyes wide and innocent.

"They agreed that they both like you!" Midoriya told her grinning. Her mouth parted slightly in realization, and the minuscule smile that she gave Twice made warmth bloom in Midoriya's chest.

"Why is it better now that Twice is here?" Eri asked him. "Can he protect me?"

"He can certainly help, right Twice?" Midoriya said, looking up at him.

Twice seemed to snap out of his thoughts, grinning. "Nothing happens to her on my watch. Of course I can help!" he said. His personalities agreeing yet again sent him back into a sort of trance, and Midoriya chuckled.

"I have another job for you, Twice," he said. Twice looked up, interested. "I need you to make a duplicate of me."

"How the hell did you know my quirk? You got it, man," he said.

"One of my quirks tells me what other people's quirks are," Midoriya explained, beaming. "Anyway, I need one of me."

"You can't make me do anything! I'll need a measuring tape to take all of your measurements," Twice said. Midoriya nodded.

"I'll get you a measuring tape, and don't worry. This is all for Eri." At the statement, Eri's eyes went wide, so many emotions shining in them that Midoriya didn't bother sorting through them all. The most prominent were gratitude and guilt, and he shook his head ever so slightly. Someday, she'd accept that he would do whatever it takes to protect her without feeling guilty about it.

He started rifling through all of the drawers until Shigaraki finally just gave him a measuring tape, and he turned to present it to Twice with a flourish. Wasting no time, Twice took his measurements, and in a few seconds, an exact duplicate of himself stood several feet away.

"Just so you know, you're the duplicate," Midoriya said as soon as his double had been created. "We gotta make sure there are no misunderstandings."

Copy-Midoriya nodded, feeling over himself. "This is crazy," he marveled. "I have all of my memories and I feel like the real me, even though I remember standing over there a second ago."

"Well, if you're me, than you should already know that I should be the one staying with Eri," Midoriya said. "You should be the one going to school and doing vigilante work."