The Enderman
The man walked along happily. He was really doing quite well: his farm was full and stocking up on wheat, he had already acquired iron tools, and no immediate worries got to him. A nice bed, a full pantry, and a good digestion.
But, as he walked along, he became forgetful. Which way was it back to his house? Eh, why not just go kill himself and go back.
He did, and was back, his mood no more for the worse. Nothing important was really on hand at the time; it didn't matter.
Unfortunately, he was unaware of how much suffering he had just caused for one particular being in the universe and beyond. Himself.
He woke. He began to gather its thoughts. Where was it? How did it get here? What was it? What was going on?
Nothing happened. Nothing happened. Just nothing.
This went on, and on.
And on and on and on and on and on and on and on.
Silence, and nothing.
Sometimes he saw other creatures: large, dark, scary black things move around him.
But slowly, memories began to return.
A dull thought here or there of a happier time; a time with brightness and colors and everything.
The bleakness, in contrast, enraged and deeply saddened him.
There was nothing, just a void.
Slowly, anger overtook him.
Anger at the world. At his state. At everything.
And particularly, against whatever'd caused this.
The agony. The terrible agony. Nothing; absolute dullness around. And he felt himself being stretched; a constant, timeless sensation. Eons passed.
He was being changed by the world and the void around him.
For there being nothing left to do, he thought. He thought of the sunshine and the flowers and the water and all the sensations: everything he'd managed to reclaim over the long years spent drifting in nowhere.
And when he opened his eyes again, he was there.
He wasn't sure what to think, but he didn't question it.
Taking up blocks, from muscle memory of doing the action countless times from days long forgotten, he began to carry them around. What for? He wasn't sure. He felt like it was natural; true.
But it also felt purposeless. Why? So much was missing. Had he been brought back just to be goaded again? What was the point of it all! He was beginning to heat again and feel frustrated.
Then he saw something moving along. He wasn't sure what it was, then it looked him right in the eyes. It was what he used to be, or something similar. Everything was going so well for it, and it angered him. Why, why wasn't it him? HE DESERVED IT AS WELL. And it was because of it that he'd been sent there. Yes, he remembered. It was the thing's fault.
In a flurry of rage, he came onto it and killed. Killed, and it felt so good. But he remembered how he'd become how he had. And he'd simply forced that on to another being. The thing he'd killed would go on, unfazed.
This enraged him all the farther.
And the Enderman was born.
A/N: There was a YouTube comment on somewhere theorizing on the origin of the Endermen, I turned this into this story. Not sure where it is now, you could probably find it if you searched enough though.