Light

Light is the main character and the protagonist of Death Note. He was bored of the life he was living and decided to pick up the Death Note, which was dropped by Ryuk (a shinigami or death god). He uses it to kill the murderer at a school and again to kill a thug who was harassing a woman. After these uses he killed all the major criminals he could find, and decided to rid the world of every criminal, thug, and "vermin" in the world.