Heart of an Assassin by Song Of Eternity is a Death Note AU in which Light is a world-renowned assassin (of the more traditional type) and L is trying to catch him.
Heart of an Assassin provides examples of:
- Accidental Murder: Light's first kill. He hadn't meant to kill the man, he was just trying to stop him from assaulting a girl.
- Alternate Universe Fic: There is no Death Note and Light is a real assassin.
- Just Like Robin Hood: Light is an assassin that only targets ruthless criminals.
- Living with the Villain: After meeting, Light and L become quite taken with each other, while both are blissfully unaware of the other's true occupations.
- Never Suicide: Light makes one of his kills look like a suicide.
- Nice Job Fixing It, Villain: The first time was an accident and Light didn't want to kill again but then the Yakuza found him and forced him to kill for them. Light agreed because the target was evil and then he returned and killed the much-feared Yakuza boss who hired him. After that Light took on the identity of Kira and the assorted criminal organizations recognized him as a freelance agent who is not to be messed with.
- Slash Fic: it's meant to be eventual L x Light.
- Villain with Good Publicity: Even though he's an infamous hitman, Kira is well-liked by the public and has a "Just Like Robin Hood" reputation.