Where am I?

I looked around the seemingly endless area I was in and saw barren land and clear, though slightly dark, skies. I was laying on a patch of grass, the only one I could see, under the shade of a tree.

I sat up, stretching my back, or at least trying to. I felt strangely small. I blinked my eyes and moved my arms into my vision, what the fuck?

In front of were two extremely chubby, pale, short arms. I guess I'm a child. I inspected the rest of my body.

My skin was a very pale tan, almost like a sheet of paper, and I was wearing shorts and a blue t-shirt, at least I'm not naked. That was all I could really see without a mirror.

A few miles away, there seemed to be a huge kingdom, walls surrounding it as high as the Statue of Liberty, and a huge castle right in the middle of it. Medieval times?

My question was sorta answered when I light blue dragon flew above me, roaring so loud it hurt my ears, and a wagon was rushing after it. Someone inside the carriage seemed to be yelling at the dragon, but I couldn't understand what they were saying. Though, I guess it could just be some people messing around with their quirk.

I leaned against my right arm, putting it on the ground, and slipped, falling down sideways. That was not grass.

I looked at where I had put my hand and there was four letters, each having four different names printed on it. Deku, Red, Uraraka, Iida.

I took the first one, 'Deku's, and started reading

Dear Kacchan,

It's me, Deku! I guess I just really wanted you to know that we all miss you. Even if you were mean to us, you were still our friend, and that won't ever change.

Okay, so he's talking about 'Kacchan', maybe that's me?

You were always pushing us, making us better, and I really have to thank you for that. Without you, I would probably be stuck at home with nothing to do and no friends.

Alright, so we have a lonely bitch here. I basically skimmed through the rest of the letters, Uraraka's and Iida's, but stopped when it came to the letter labeled 'Red'.

I tore it open

Dear Bakubabe,

Yo! It's me, Kiri! I just wanted to write you a letter, saying a few things and explaining my view.

A shiver went down my spine.

I think you're wonderful. You're so beautiful, smart, fantastic, and keep surprising me in the strangest of ways. Like those drawings, they were so pretty, I wish you could draw more of them.

Another shiver, and what seemed to be a blush formed on my face

I didn't think I was enough for you, you always seemed to outclass me in every way, but I loved you none the less. You were just... so you.

Something wet rolled down my face.

I know this may not sound very like me, but I don't really care if you're not manly, you're still my little wolf, and nothing can change that.

At this point, I was full out bawling. I couldn't read anymore, and I didn't know why. Why did this letter make me so... sad? I don't have any sentimental connection with this letter or person, so why did it seem to mean so much to me?

Who was 'Red'?