Smoke Monster...What a Bald Head You Have!

If memory serves, there are a total of three people who appear on the island after they are already dead: Yemi, Christian, and of course (SPOILER ALERT) Locke. All three characters' dead bodies are also on the island: Yemi lies in the drug plane, Christian's coffin is at the caves -- and god knows where his body got to in the crash, and Locke's body is in a giant crate which those new people carry around in the final episode of season five.

There are other people who appear on the island or appear to characters when they "should not" such as Hurley's asylum buddy and Walt with his crazy water speak, but these appearances are for another discussion.

At the end of the fifth season, -- let's call him the Omniscient Locke -- references a "loophole" discussed in the first scene of the episode by the Man in Black and Jacob a few hundred years earlier -- give or take fifty years. Since Omniscient Locke is speaking directly to Jacob when he references the "loophole," the only person that Omniscient Locke could possibly be -- assuming no one else overheard their ancient convo -- is the Man in Black.

To sum up: Omniscient Locke = The Man in Black

Here's where things get fun:

In the sequence where Omniscient Locke brings Ben Linus into the temple to face the smoke monster, Ben falls below while Omniscient Locke stays above the confrontation -- completely unseen for the duration. Only when the smoke monster disappears again, does Omniscient Locke appear again. There's a reason that Superman and Clark Kent are never in the same place at the same time. Furthermore, when Jacob and the Man in Black speak at the beginning of the season five finale, Jacob makes reference to bringing people to the island while the Man in Black prefers to keep them away and protect the island. The only other protection the island has: the smoke monster -- a type of security system, as described by Ben Linus.

To sum up: Omniscient Locke = The Smoke Monster

The fact that the only other two dead bodies on the island are the ones which appear to people as real as real can be -- without people being in a state of insanity or finding themselves overwrought with fear -- tends toward the idea that the smoke monster can take on the forms of any dead bodies on the island. Yemi appears to Mr. Eko after the smoke monster approaches Mr. Eko and reads images from his memory -- we see glimpses of Mr. Eko's past in the translucent black clouds during the stand off. How else would the smoke monster know what form to take in order to engage Mr. Eko? Omniscient Locke says to Jacob in the final scene of season five that he had to go through a lot to get the loophole to work out -- Read: The Man in Black had to make sure he learned all he could about Locke in order to pass without concern, but more importantly, he needed to make sure that Locke killed himself and got his body on the plane; only in this way can the smoke monster take on Locke's form, becoming Omniscient Locke.

To sum up: The Man in Black = The Smoke Monster -- sure the transitive property would have worked just as well...

To wrap up: Omniscient Locke goes out of his way to make sure that Richard tells Locke that he will have to die. Locke takes this as a Truth and tries to off himself while off the island. Ben stops Locke's suicide attempt and then finishes the job. This is a moment of incredibly good fortune for Omniscient Locke, who needs John Locke -- the man who has become the leader of almost everyone on the island -- to come back to the island, dead, so he -- the man in black -- can take John's form, leading the people to confront Jacob, and at last kill Jacob; Man in Black: "Do you know how bad I want to kill you?" Jacob: "Yes." Well, the Man in Black sure found his loophole.