Harry James Potter was bored. It was the last day of the year at Hogwarts, and everyone would head home the next day. He had absolutely nothing to do other than chess with Ron or reading with Hermione. Neither one was especially attractive at the moment. He was craving adventure. Not the life-threatening adventure he was usually subjected to, but a new place to explore. At the end of his second year, he'd explored most of the castle, except the secret passageways, house specific areas, and the chamber of secrets.
"The chamber! I can explore the rest of it! See what's down there," he decided.
Harry grabbed his broom, his invisibility cloak, and some snacks in case he got hungry. He began walking down stairs. He passed the others. It looked like Ron and Hermione were arguing again. He decided to leave them to their fight and head downstairs by himself. He entered the lavatory and commanded the entry to open.
Harry descended down through the tunnels beneath the second floor girl's bathroom. He wasn't sure what he was searching for as he went through the chamber, only that he suspected there were more secrets to discover than the, now deceased, basilisk. Of course, that itself might still have uses. He briefly entertained the thought of harvesting it. He decided that could wait until he was done exploring.
One thing Harry always acted on was his curiosity, and given how things had been, he was sure he had saved a number of lives that way. During his exploration of the side chambers, the floor suddenly shook and dropped down on one side, forming a ramp. Harry staggered and fell, skidding down the inclined stone surface. He came to a stop on a cave floor. He shook his head clear and looked around. Young and inexperienced as he was, even he knew this was not a part of the chamber above. The walls and ceiling were entirely different. He didn't know the words to describe the difference, but had an archaeologist been there, he or she would say that the stone work was entirely different and that judging by the weathering, this place was immensely older than the chamber above.
Harry felt a burning desire to explore, to learn. He lit his wand with a quick lumos and began wandering down the tunnel in what he guessed was the direction of the forbidden forest. As he went the tunnel continued to go deeper underground. Not quickly, but enough to be noticed. The tunnel stretched for some time. Harry was sure he was far into the forest by now.
When he finally got out of the tunnel, he was in a massive cavern, large as the quidditch pitch and just as tall. Ten feet ahead of him was a large building. It was at least three stories tall, and made out of some sort of metal. At each corner of the building there were rounded pillars, almost like… muggle rockets.
Harry looked away from the structure and saw a ghastly sight: Corpses. Some were blue-skinned and mouth-less creatures in gold armor with inlaid Crystals. Others were purple and black creatures that looked like crossbreeds of every creature he'd ever seen and many he hadn't. The rest were massive suits of some kind of red and black armor, containing what looked like human skeletons. There had to be close to six hundred corpses scattered throughout the cavern, dotted with broken down machines of different sorts. Harry had no doubt he was standing in the remnants of an ancient battlefield.
Harry looked at the building, it was the only thing untouched by the rampant death and chaos. It was in pristine condition, not a scratch on it. Harry walked around, finding its' entrance on the opposite side. He reached out to touch the door, only for it to split down the middle, opening as the two halves slid apart.
"Wow," he'd never seen anything quite like this place, certainly not in the magical world, where wood and stone buildings were the main stay.
Harry walked through the door, and looked around. The chamber had half dozen large machines that Harry couldn't tell the purpose of. He did notice one thing: the lift. It still had power. Its' light was on and everything. Harry walked into the lift and looked at the control panel. Not being able to read the strange non-english labels, he pressed the button that was lit up. He exited the elevator into a room full of computers. Standing before him, he couldn't believe it, was a robot! It buzzed to life.
"New Commanding Officer detected! Begin System Assimilation!"
"WHAT?" was all Harry had time to scream before the robot hit him with an arc of electricity, knocking him unconscious.
Harry awoke some time later, he rubbed his head. He felt different, his mind was much more… clear?
"Computer, what's going on?" he asked.
"You have integrated with the control functions and data archives of the command center's electronic network," the robot, he now knew was called an adjutant, answered.
"So I have full control and know everything this base does?" Harry inquired.
"Affirmative," the adjutant confirmed.
"Wouldn't I have to be a Terran for that? And a psion no less?"
"Terrans are basically human with a few genetic mutations resulting from their ancestors' long isolation from traditional humans. Your genetic structure was easily altered to match the terran genome. You are terran now. As for psionics, you already had a vast amount of psionic power you simply did not know how to use it yet."
Harry stood and walked to the command center's observation deck. He gazed across the wide battlefield, able to identify the bodies. Those blue-skins are Protoss. The creatures are Zerg. And the men in powered armor, are Terran. Harry stood over the vast grave, the full impact of his new power and knowledge finally reaching him.
"Sir? Are you well?" The adjutant asked hesitantly.
"Just reflecting on my new position and the consequences of that position," Harry spoke.
Harry took a deep breath and made his decision.
"I am General Harrison James Potter of the resurgent Terran race. I will lead my people to prosperity. Even if I have to tear down this magical world to do it," He said, with the conviction of a man whose entire race rested on his shoulders.
Harry Potter's property disappeared from his dorm that night. He wasn't seen on the Hogwart's express the next day. Nor was he seen at King's Cross. And never again would he set foot in number 4 Private Drive.
Author's note: For those of you curious about the differences between canon Terrans and traditional humans... I can't help you. In this story however the answer is easily explained. Terrans have been isolated from typical humans for many centuries and have slowly deviated from their parent race. Terran muscular and skeletal systems are better developed, stronger and more resilient. Terran immune systems have strengthened considerably. Terran biology is all around tougher and more combat oriented than typical humans, and adaptation to the harsh conditions of their home sector and it's constant wars. Unfortunately, Terrans are also more prone to aggression and violence than other humans. It is theorized that this is because of the oppressive nature of their past governments and the fact that most terrans are descended from violent criminals. Aggression is in their blood, as it were.