Just so you know, this was not crafted for this section, and was written on the fly. So please, if you know anything that can be improved, tell me in the comments.
In this story, the Endermen were the most proud civilization in Minecraft, once. For the most part, the End really was just like it was now, except for the fact the it was covered with life.
The Endermen were masters of biology, robotics, and war. They created pigmen as their slaves, and made the first golems to enforce rule. Their cities stretched higher than mountains, thier ships faster than anything else.
Then, one Enderman, so proud, so arrogant, ignoring all warnings, opened a portal to the Dimension of the Darkest Evils. It sucked him in it, transforming him, until he looked completely different from any other enderman. Originally, Endermen were red skinned, and had green eyes, but this one was jet black, and had purple eyes. Beyond this, he was stronger than any regular Enderman, and could warp himself through an infinite number of dimensions. He could also change his fellow Endermen with his disease. The pigmen were even more susceptible to the disease, as it made them zombie-like.
This caused a massive panic, and the golems were dispatched to destroy him. He barely lifted a finger as they fell through the void. At last, the entire enderman civilization fell, and the true evil, the Dark Dragon, made the End her domain, forcing the endermen to do her bidding, such as tearing down their cities, and giving her many gifts. That''s why the endermen go everywhere, to keep their zombie-pigmen in check and to bestow gifts to the dragon.