What if the real Obi-Wan Kenobi was killed on Tatooine, and Ben Kenobi had promised the dying Jedi Master, Obi-Wan Kenobi, before his death to look after Luke Skywalker. It wasn't until fourteen years later after his death that Darth Vader realized that Obi-Wan, his former master, was dead.
After Voldemort hexed Harry. Harry quickly found out that there's no one here in the wizard's world even giants or goblins. Harry quickly realized that he's the last wizard of the century by Vodie's unknown and ancient curse that strike Harry. Harry only the bearer of magic and the last half-blood prince and the last heir of Potter line.
Harry's seventh year that lead a final battle between the boy who lived and the darkest wizard of the century since Merlin's time, Voldemort sent one final Killing Curse on Harry, but it rebounds, striking Voldemort and destroying him once and for all. The wizarding world returns to peace once more. About ten years later the-boy-who-lived felt deeply ill and laying on his deathbed.