Lost explained. Charlie is a zombie by Jonathan L. Wielbruda

I'm tired.

Yes, I am going to use the word zombie throughout this post. Darlton conned us into thinking their "zombie season" talk was a joke this whole time.

Let's assume that when a person dies, if they remain unburied then they MAY get claimed by an entity bringing them back to life. Burial obviously makes it difficult to get back up and walk around. (Expose is genius in hindsight. Two people - not dead yet - showing the difficulty.)

So Sayid - definitely a zombie. His behavior mimicked that of Claire after her house exploded, so she's a zombie too. They are walking around, but they are dead. Dead is dead. Who else are we told is dead, but walking around? Christian. Explains why his body is missing.

Jin MAY BE a zombie. That freighter exploded nice and good, and MiB-as-Christian (different than Zombie-Christian) was already out there...

Charlie is clearly a zombie. Dead Charlie was not a ghost to Hurley in the institution. Someone else saw him. He was dead, but he was also there. Zombie! He was our only main cast member who has died without being buried. ZOMBIE!!! (And working for the MiB I think.)

Locke is not going to become a zombie, because he already is one. Jacob made him one after he fell out of the window and stuck him in a wheelchair until it was time for him to play. This is why MiB is posing as Locke instead of possessing, because he can't have him. The respawning pool in the Temple can bring him back. Maybe the others thought Sayid was already a Jacob zombie (like them?) but killed him instead, inadvertently allowing him to be claimed by MiB.

Rambling over.