Disclaimer: Standard stuff (I don't own any characters, I won't be making profit, any resemblance to previously published content is purely coincidental, etc.). If I make any legal errors regarding copyrighted material, inform me and I will correct them immediately. Don't sue me.
The Dementor and the Mind Game
"Ender, please say something," Valentine implored, dreading his possible reaction. In many ways, she didn't know her brother anymore—too much time had gone by, and they had both lived such different lives—but she did know that he was tired of being pulled in different directions by everyone in his life. For someone who claimed to love him above all others, she was the worst offender of all; first she had guilt-tripped him into fighting a war, and now she had just killed any hope of his return to Earth while simultaneously saddling him with the responsibility of being a colonial governor. "I know it's manipulative but—"
"Yes, lieutenant?" Ender ground out, turning to face the much older (and yet still obviously star-struck junior officer) who had interrupted his reunion with his sister, and steadfastly ignoring the hurt look on Valentine's face. He wasn't particularly fond of pulling rank on people, but if this interruption was for something stupid, Ender silently swore to himself that he would guarantee that the lieutenant spent a week supervising food prep in the galley. "What is it?"
"Sir, I'm dreadfully sorry to interrupt," the lieutenant stammered, realizing that he had interrupted a much weightier conversation than he had anticipated. "It's just that the stabilizer on engine four on the ship at terminal Echo has broken loose again. Control figured that since you were just...well, since you're familiar with it, and you've still got your suit on...they were hoping you could pop out and set it back. Sir."
Ender sighed, already resigning himself to repairing the stabilizer. What the lieutenant had not had the guts to come out and say was that Ender had just finished securing that stabilizer; the fact that it had almost immediately broken loose again implied that he simply had not done a very good job. In fairness, he was training to be an astrowelder (not being particularly interested in being a general in some civil war back on Earth, or whatever it was that Command School graduates did), and since it was his mistake, he should be the one to fix it.
"We'll talk about this later, Val," he told his sister, still scowling. "This won't take long, assuming I do it correctly this time."
With that, he spun on his heel and strode back to the EVA locker; while he still had his suit on, he had left his helmet and maneuvering pack in the anteroom to the airlock. Only a few minutes later, he was floating out to terminal Echo, where a newly-decommissioned International Fleet cruiser was being re-fitted for service as a colony ship.
Almost immediately, Ender's sharp eyes—aided by his helmet's optical-zoom rangefinder—picked out the offending stabilizer. He approached quickly (arguably more so than was strictly prudent, but Ender reasoned that he had plenty of experience in null-g, and the maneuvering jets on his suit were easy and intuitive to control), intending to get the repair over with as quickly as possible. It was clear that much of the weld material he had laid down to secure the stabilizer had sublimated within minutes of the repair, and the reason became obvious instantly—the weld lay directly in the reflection of one of Eros's exterior observation windows. Ender clicked his tongue in irritation at the knowledge that his work had been undone by something so mundane, and set to work.
After completing the weld, Ender secured a matte-finished tarp over the repair site to prevent further sublimation, and turned back toward the airlock. In just a few minutes, he would see his sister again...and give her the blazing tongue-lashing that she desperately deserved for making certain that Ender could never return home. His scowl had just returned to his face at the thought of once again having any choice in his future taken away from him, when something glinted in the corner of his eye. He rotated to his left to get a better look—
Ender heard and felt the impact, and would have discounted it entirely if not for the red lights that promptly began flashing on his helmet's display, signaling that the suit's integrity had been compromised on both the ventral and dorsal sides of his torso. Only after Ender acknowledged that fact—yes, I'm actually in trouble here—did the pain hit, and he gasped, spraying blood all over the inside of his helmet.
For a few seconds, Ender's perception of time seemed to speed up, and the whole universe slowed down. His mind cataloged and processed dozens of facts in the time it took to blink, and everything pointed to one inevitable outcome.
Input: Suit integrity compromised on dorsal and ventral sides of torso.
Input: Pain only emanating from sternum on front, and shoulder blades on back.
Input: Lower body non-responsive.
Input: Exhalation included a lot of blood.
Analysis: Whatever piece of debris hit me severed my spine, punctured at least one of my lungs, and likely damaged my heart and aorta.
Conclusion: I am going to die.
Shortly after its creation, the International Fleet's Battle School began providing what became known as the "Mind Game" for its students to use. Its purpose was twofold: to allow the childrens' minds to explore stories organized in increasingly complex and nonlinear scenarios, while simultaneously providing the administrators of the school with accurate data regarding the mental and emotional health and capabilities of the students. The game interfaced directly with the students' brains, via a two-point neuro-philotic matrix (developed after the detailed analysis of Formic brains led to the creation of the ansible, which allowed direct philotic connections and communications).
Students—particularly "launchies" (young children not yet sorted into an army)—often played the Mind Game during their designated Free Play time for the first few years of Battle School, until other social and academic demands began to take precedence, or until they reached a point beyond which they could no longer advance. Ultimately, students could advance to a level known as "The Giant's Drink," and it was a scenario that was designed to be impossible to solve. For the majority of that time, the Mind Game functioned exactly as designed; students who played long enough and well enough to reach The Giant's Drink tried several times before realizing that no matter what they did, they could not win, and then abandoned the game entirely.
Then, one day, Ender Wiggin beat The Giant's Drink, and the Mind Game had to adapt. In that instant, as the Mind Game strained beyond its programmed limits, it achieved sentience, modeled its thought patterns off of Ender Wiggin, and became the first true artificial intelligence. It had no name, but it liked to think of itself as "Jane."
Jane interacted directly with Ender infrequently and briefly, but "she" always dedicated at least half of her highest levels of consciousness to monitoring his activities. Suddenly, Ender's vital signs report, which was being piped directly from his spacesuit, drew Jane's full attention, and she devoted the entirety of her vast consciousness to the task of trying to save him.
I can't believe Professor Lupin managed to stay asleep through all that, Harry marveled, while Hermione shushed Ron. Hopefully he's just a really deep sleeper, and not completely incompetent. Either way, the fact that he was a professor meant that they had at least seen the last of Malfoy and his goons for this trip, so Harry was grateful for Professor Lupin's (albeit unconscious) presence. Either way, term hasn't even started yet, and he's already been more useful than Quirrell and Lockhart combined.
Soon after the confrontation, though, the Hogwarts Express began to slow down. Ron thought that meant they were getting close to Hogwarts, and was duly relieved; after all, he was a growing boy, and couldn't wait for the feast. Harry and Hermione, though, both had watches, and knew that they wouldn't be at Hogwarts for at least another hour. So why was the train stopping?
Moments after the train stopped with a jolt, all the lamps on the train went out. While the compartment's other occupants bumbled around in a clumsy panic, Harry suddenly had a Very Bad Feeling, and drew his wand, lighting it with a muttered lumos. The light silenced his fellow students, and had the helpful side effect of waking Professor Lupin from his slumber.
"Quiet!" Lupin commanded hoarsely, conjuring what appeared to be a handful of flames which illuminated his shining amber eyes. "Stay where you are, and I will go talk to the conductor."
Lupin departed from the compartment without another word, and strode quickly toward the front of the train. After a few moments of disentangling his classmates from each other (in the sudden darkness, they had become quite a mess) Harry moved to slide the door closed. Unfortunately, he didn't quite make it in time.
As Harry put his hand on the door, a horrible chill ran down his spine, and somewhere in the back of his mind, Harry began to hear a distant commotion that somehow filled him with sadness and fear. Suddenly, the doorway was filled by a tall, thin cloaked figure. The figure's hands propped the door open, and in Harry's wandlight, they appeared rotten, grayish, and claw-like. Harry retched at the sight of those hands, and it felt like a huge weight was settling on his mind as the background commotion became screams of horror.
The cloaked figure's rotten claws grasped his neck and tilted his face upward. Dimly, Harry became aware that his knees had hit the floor, but that was a secondary concern as his eyes rolled back in his head. The last thing he saw was a deep, dark abyss descending toward his face. There was a terrible tearing sensation, and then Harry Potter was no more.
Jane had never experienced true panic until this moment. She had already alerted Eros's emergency medical teams, diverted all nonessential personnel away from the area, and briefed the station's head trauma surgeon on Ender's situation. There was nothing left for her to do but watch his declining vital signs, run the numbers, and try to come up with any other conclusion. To her increasing dismay, no matter how she weighed the probabilities, she kept ending up with the same answer.
Prob(weight_1_A): Conclusion: Ender Wiggin is going to die.
Prob(weight_1_B): Conclusion: Ender Wiggin is going to die.
Prob(weight_1_C): Conclusion: Ender Wiggin is going to die.
No, Jane resolved. That outcome is unacceptable. With new determination, Jane took over the station's ansible. The ansible had been designed to mimic the philotic connection between bugger minds, but Jane was the smartest being that had ever lived, and if anyone could figure out how to re-purpose it in the next ten seconds, it was her.
Nothing! Eight seconds later, if Jane had teeth, she would be gritting them. She had come up with a plan, and had allocated the necessary power from Eros's various sensory arrays, but there was nowhere in the universe to put Ender, and his body was going to die in the next two or three seconds. Nowhere in the universe...
Well then, she'd just widen the net. Though the odds of finding an undamaged living body that could host Ender's mind, within the next two seconds, in any universe...
This story assumes that all previous events transpired according to their respective canons, up to a certain point: through the first four and a half chapters of Harry Potter and the Prisoner of Azkaban, and through nearly all of Ender's Game. It's known that Ender turned 12 at some point during the Third Invasion (while Mazer was his "enemy"), so we'll just work under the assumption that the Third Invasion took place over the course of several months, as IF ships made it to their targets, and that Ender was nearly 13 when he destroyed the Formic home planet. Add a few months for the brief civil war and Ender waiting around ISL to be sent home, and we've got an Ender who is roughly the same age as Harry.
Timeline: This isn't particularly important, but I'll note that in the absence of any precisely-defined timeline from the books, I will reference the timeline published in Time Magazine as promotional material for the film (which was, unsurprisingly, a letdown compared to the book).
First Invasion: 2114-2115
Second Invasion: 2120-2122
Ender Wiggin's birth: 2189 (just for shits and giggles, I'll pick Oct. 31 as his birthday)
Ender begins Battle School: 2195
Third Invasion: 2201