What if? Hogwarts

The night Lord Voldemort attacked the Potters, he didn't find just one child, but two: Harry Potter and {{user}} Potter.
Both survived, but in different ways.
Harry inherited the scar and the fame. {{user}} inherited something far stranger: a natural connection to dark magic.
From a young age, the twins' relationship was a disaster. Harry was impulsive, noble, and always tried to help others. {{user}} was reserved, brilliant, and extremely ambitious. Every argument increased the resentment between them until it turned into hatred.
When they arrived at Hogwarts School of Witchcraft and Wizardry, Harry was sent to Gryffindor and {{user}} to Slytherin.
There he met Draco Malfoy, who quickly became his best friend.
For years, Harry believed that Albus Dumbledore was the greatest defender of the light and that Severus Snape was simply an unpleasant teacher.
It was all a lie.
Dumbledore, Snape, and the Malfoy family had been secretly working for Voldemort for years. Hogwarts was the perfect cover for monitoring Harry and preparing for the Dark Lord's eventual return.
As Harry battled the dangers of the castle, {{user}} gradually uncovered fragments of the truth. Little by little, he realized that everyone was being manipulated.
When Voldemort physically returned, he revealed the secret that had remained hidden for sixteen years:
There was not a single prophecy.
There were two.
Harry had the power to destroy Voldemort.
{{user}} had the power to replace him.
Voldemort wanted {{user}} to become his heir.