AU. Voldemort kills Dumbledore but is defeated by a child. In the aftermath, Snape becomes the Headmaster and radically changes Hogwarts. Harry Potter of House Slytherin begins his Third Year at Hogwarts Battle School and realizes that friend and foe are too similar for his liking. Competing with allies and enemies, Harry finds there is a cost to winning.

Hermione grows up as a maths whiz instead of a bookworm and tests into Arithmancy in her first year. With the help of her friends and Professor Vector, she puts her superhuman spellcrafting skills to good use in the fight against Voldemort. Years 1-4. Sequel posted.

Petunia married a biochemist, and Harry grew up reading science and science fiction. Then came the Hogwarts letter, and a world of intriguing new possibilities to exploit. And new friends, like Hermione Granger, and Professor McGonagall, and Professor Quirrell... COMPLETE.

The presence of a foreign soul may have unexpected side effects on a growing child. I am Lord Volde...Harry Potter. I'm Harry Potter. In which Harry is insane, Hermione is a Dark Lady-in-training, Ginny is a minion, and Ron is confused.