On the Island....
She is the leader of the Tail-section survivors. She is hard and
tough, but that probably has something to do with the fact that the
tail section survivors have been reduced from 23 to 5. She was tossed
into the prison-pit as a ruse to try and find out who Michael, Sawyer
and Jin were. She was surprised to discover that they were on a
Sydney-Los Angeles plane. She asked “Flight 815?," and Michael, Sawyer
and Jin were surprised to learn that she was on the plane too. When she
learned that Sawyer had a gun, she questioned him about it. When he got
suspicious, she hit him and took the gun, and asked to be hauled out of
the hole.
After discussing it with the other tail survivors, she
released the raft people from the pit and took them to their base, an
old and non-operational DHARMA Initiative station, "The Arrow."
She decided that the tailers would go and try to find the rest of the
crash survivors on the other side of the island. When Michael ran off
into the jungle looking for Walt, Ana-Lucia immediately prepared to
leave before the Others could find him and come for the rest of the
tail survivors. Jin and Eko left to look for Michael, even though
Ana-Lucia said she was not going to wait for them. She believed that
Eko would catch up with them, which he did.
Ana-Lucia didn't want to go inland for the sake of Sawyer. She
considered him a dead man walking, but Eko insisted so she went,
warning him that any more deaths or kidnappings were on his head. She
also didn't like stopping while a stretcher was fabricated for Sawyer,
but they waited.
When Cindy vanished just after the survivors struggled to get
the unconscious Sawyer up a steep hill, the whispers started. Ana-Lucia
told everyone to run. In the midst of some loud whispering, Ana-Lucia
shot a moving figure. It was Shannon.
Realizing that she had made yet another mistake, Ana-Lucia
snapped under the stress of the previous 48 days. She had Sayid tied up
to give her time to think. But that meant dismantling Sawyer's
stretcher, so Eko abandoned her to carry him to the fuselage camp. When
Libby and Bernard wanted her to let Sayid go, Ana-Lucia made a plan -
she would get supplies from the fuselage camp, and then go off into the
jungle to live by herself. She sent Michael to give her demands. Libby
and Bernard refused to be a part of that any longer and left her,
taking Jin with them.
Ana-Lucia asked Sayid if she should kill him. He told her that
he is still haunted by the terrible things he's done in his life.
Ana-Lucia told Sayid that once she hesitated to use her weapon and she
got shot four times. She said that she feels dead.
She didn't make excuses, or ask Sayid not to kill her. She
didn't try and make him feel sympathy to her, she didn't run away into
the jungle. She let Sayid go, gave him the weapons and told him he
could kill her. Ana-Lucia took responsibility for her actions. Sayid
said that there was no point in killing her since they were both
already dead inside. They headed back to camp. Ana-Lucia met Jack and
Eko in the jungle.
She is staying on the beach and mostly keeping to herself. She
didn't attend Shannon's funeral for fairly obvious reasons. After Jack
encountered the Others in the jungle, he came to her and asked her how
long she thought it would take to train an army. Unfortunately, Sawyer
was able to use Kate's distrust of Ana-Lucia in his con to steal the
weapons from the Swan's armory, effectively putting an end to Jack and Ana-Lucia's "army."
After Henry Gale was caught and brought to the Swan, Locke
asked Ana-Lucia to interrogate Henry as she was a cop and has
experience. She was able to talk Henry into drawing a map to his
balloon, and she, Sayid and Charlie found the balloon and the truth
about Henry Gale. After being overpowered by Henry when she let her
guard down, Ana-Lucia was able to steal a gun from Sawyer after having
sex with him in the jungle. She planned to kill Henry, giving him the
knife she got from one of the Others she killed and ordering him to cut
himself free, but Henry told her how Goodwin thought she was
misunderstood and how he believed he could change her. Ana-Lucia
couldn't bring herself to pull the trigger and locked Henry back inside
the armory. As she sat outside the door and contemplated things, the
recently returned Michael asked her for the gun and combination to the
armory, telling her that he'll shoot Henry. Ana-Lucia gave him the gun
and combination, but Michael shot and killed her.

Other Links:
Flashback Cast and Summary - Exodus 1
Flashback Cast and Summary - Collision
Flashback Cast and Summary - Two for the Road
Broken Families - Ana and Captain Cortez
Character Connections
Character Parallels - Saved a Life
Character Parallels - Therapy
Character Parallels - Bondage/Held Captive
Character Parallels - Sign on the Line
Character Parallels - Took a Life
Character Parallels - Aliases and False Identities