I’m thinking that anyone who kills someone on the island dies. Think about it. Desmond has consistently foreseen Charlie’s demise, but Charlie seems to be destined to die. Anna Lucia killed someone, and she’s dead. The reason the others wanted John Locke to kill his father is to see if he’d die. If he doesn’t, he must be special.  Sawyer killed Locke’s father instead, so now we’ll have to see if Soyer dies. Who else has killed someone on the island?  Mr. Eko has. He’s dead. Juliet has, not dead yet.  So has Sun. Sun’s going to die because she’s pregnant, and pregnant women die on the island.
Maybe there’s someone who doesn’t fit here that I’m not thinking about. Â Another thing I wonder is what happened to Michael and his kid.