After placing Harry at #4, Dumbledore went back to Hogwarts. He knew Voldemort would be back. He could feel it. And there was no way the Light would cower this time. He remembered the Grindelwald war; how hard it was, and he had been a fool to assume that it would be different this time. No... his side had to be prepared for when Riddle came back. Welcome to Hogwarts Battle School.

HP/Ender's Game Crossover - After defeating the Formics, Andrew "Ender" Wiggin decides that he's done with war, and begins training at the ISL docks for a normal, quiet life as an astrowelder. Unfortunately, a hungry dementor and a computer program named Jane have other plans, so Ender finds himself at Hogwarts...and magical Britain will never be the same.

A century ago, an alien armada appeared from the depths of space and threatened the human race with complete extinction. As the Muggles were driven toward greater and greater desperation, within the Wizarding World the decision was made to emerge once more and provide the necessary aide to keep them all alive. FULL SUMMARY inside.

Ender shifted through the huge pile of letters in the box at the foot of his bed. Where should he begin? He braced himself. This was painful, but he had to know. Because if he knew, he could find her.

"We won the First War, but just barely. If it wasn't for a stroke of brilliant protective magic by your mother and father, and your own innate strength and unfathomable talent, magic would not exist in the form it does today." One-shot, COMPLETE.