Izuku Midoriya, as known as "Deku" was just doing his daily hero routine. He thought to himself, "I honestly can't believe that All Might wanted me to do this." 

"Izuku, as you know that you're a Pro Hero, you have to do a daily routine in case of anyone is in danger!" 

He coughs up blood, as Izuku screams, "You're bleeding again, All Might!" 

All Might cleans his stain of blood, "At any rate, you have to be cautious at all time." 

The Pro Hero sighs, "Why wouldn't any of the Pro Heroes take it seriously?"

That was when something felt a little bit off. 

He looks up, to see a girl, who has orange hair falling down from the sky, as she was screaming. 

"Oh, crap! I have to save her!" 

He thought, "All For One, 20%!" 

The girl was carried by Izuku as the girl was shocked . "What just happened?"

They landed in safely on the ground, as that the girl looked around, "Where is my gun?"

"Your gun? Is that your Quirk?"

She notices the gun straight away, as there was something else. 

A big monstrous creature came up, as the girl said, "You have to run. " 

"Excuse me?"

"You have to trust me on this, that demon is dangerous, I know how to deal with this." She said, as she was loading her gun. 

"No way! I'll handle this. This is no problem for me. " 

The girl was surprised by his attitude, like she seems to be smiling. "Well, I think you should let me . I have some near death experiences before." 

But Izuku didn't exactly listen to her, as he said, "Sorry, but this is a Pro Hero's job. If I don't, I wouldn't call myself a hero!" 

He races through the street as the girl was amazed of how fast he ran. 

"He's fast!" She exclaimed. 

As the Demon see Deku, he thought, "Time to see what this thing can do with this! Manchester Smash!" 

The attack didn't effect on it, as he thought, "No way! How can it not work?!?"

"Thanks for the distraction, that was perfect! " The girl said, as she shot the Demon down, as it lies dead on the ground, as the girl collapses on the ground. 

"Hey!" Deku exclaimed, as he carried her to the Dorms at U.A. 

"You don't know where this girl came from?" Bakugo asked. 

"Sorry, Kacchan , I don't know where she came from, but she is very determined . She didn't faze at all . " 

"She's waking up." He said, as the girl said, "Ooh, my head. Oh, how did I get here?"

"I carried you here. I'm Izuku Midoriya, but my friends just call me , Deku, the one beside me is Kachan. " 

"I'm Emma. " Emma introduces herself, "So, where am I exactly? Am I in the Demon Forest?"

" 'Demon Forest? You better explain right now!" Kachan exclaimed, using his fire quirk, as Izuku tries to call him down, "Calm down!" 

"I take it you're not from this world, aren't you , correct?" 

"All Might?" Deku asked. 

The Pro Hero asked Emma and Deku to go to his office. 

"I take it that you didn't mean to come here. Can you tell us where you come from?"

"It's a complicated. " Emma said, as she touches her left ear. As though, Anna would've change the bandage, before she bleed out. 

"I suppose that you have some bandages, do you? I needed this to be changed." 

"I'll lead you to Recovery Girl, if you want. She's the medical Pro Hero." Deku said. 

As he leds Emma, she wonders of she will be able to find out why she was sent to a different world, and would her family will wonder where she could be?

AN: 

I love My Hero Academia and the Promised Neverland, so I thought of this crossover. I hope you like it.