It seems as we learn more about each character they have some categories they fall into:

Killers (Pre-island & post island):
Kate- Killed her dad
Sawyer- Killed at least one dude & attempted to do the marshall
AL- Killed at least one man in cold blood &killed a few OTHERS
Eko-Killed a few people on and off the island
Sayid-As a soldier in war may have killed people, may have killed some as an interagator

Blamers:
Jack- as a Doc may not have 'killed' but BLAMED himself for deaths
Hurly- we learned that he BLAMES himself for the death of two people

Violent:
Jin- enforcer for Korean Mob boss, but wanted out

Innocents??:
Locke- Was angry at the way life turned on him, and BLAMED himself and was looking to prove that he could do it but appears to have been a decent guy.
Claire- Manipulated by the Psychic
Walt- With dad
Boone- manipulated by Shannon after step dads death
Michael- here because of the death of his Ex
Shannon- manipulated men to get abck at step mom after fathers death (inc Boone)
Sun- was working an angle to get away from Jin
***Charlie- by brother, drugs, and ultimatly by being on the island to become a killer

Note:
Some of the Losties can fall in to more than one of my 'categories'

***Charlie is the only one who seemed to be lead straight down the Dark Path from the earliest flashbacks. Boone and Shannon are dead and Walt and Micheal are taken. Sun & Claire are still clinging to their values.

After hearing Hurleys back story more in depth I just wanted to share this.