Voldemort

Once thought to be dead after the incident with Harry Potter in the first book, he is known worldwide as You-Know-Who because of their fear of the evil Tom Riddle, a.k.a Lord Voldemort. Voldemort seeks revenge on Potter and because of his weakness, he shares the soul of Quirrel, one of his Deatheaters. He infiltrates Hogwarts with Quirrel and fails as Quirrel melts because of Potter's mother's spell and Voldemort is forced to go into hiding once again. Later, he gets his body back and nearly kills Harry in almost every book and fails each time until he finally gets the Elder Wand, which was proved to be invincible and he attacks Harry in the last book of the series, once again, Voldemort's luck turns against him as Harry blocks his killing spell and it ricochays back and hits him in the chest. Like all the Elder Wand owners, he dies.