Lobo: The Last Czarnian

Born on the peaceful and tranquil world of Czarnia, the ultraviolent interstellar bounty hunter Lobo decided one day to kill everyone on the planet so that he would be unique. But years after his massacre of over five billion people, the lunatic assassin learns that one other person from Czarnia still exists, his fourth grade teacher Miss Tribb. Infuriated by the news but bound to duty, Lobo finds himself protecting his teacher from a slew of attackers as part of his latest mission. But in the end, the alien's bloodlust wins out and Lobo truly does become the last of his species when he breaks the neck of his former instructor.