Jacob the Supplanter, and the identity of his nemesis by CinematicESP

Here's a thought...

Jacob, like "Nemesis," has the ability to take the shape of dead people. Jacob is actually inhabiting the body of Nemesis, rendering Nemesis formless. He is the black smoke monster. This is why he wants to kill Jacob so badly, because Jacob stole his identity. (The name "Jacob" does mean "supplanter" after all). The Man in Black at the beginning of The Incident is simply Nemesis taking the shape of a corpse. Perhaps he killed this person and assumed their form in order to have the conversation with Jacob. This could be what he meant by "I just ate."

As for his identity...

Nemesis is a grown up Aaron from the future, perhaps the result of not being raised by Claire. This is why Jacob now looks like a grown up Aaron (blonde, blue eyes). It also explains how, as "Christian Shephard," he was able to hold baby Aaron (himself), but not touch anyone else (like Locke), at least until he found his loophole. As Christian, he made sure that Claire was separated from Aaron, forcing him to be raised by another and thus becoming an evil nemesis that Richard Malkin foresaw and tried to prevent...

There must be a good reason why Nemesis' name was not revealed to us in The Incident, probably due to the fact that it's a character we already know. It beats a having a brand new character introduced at the very end of the series. And it also explains the apparent importance of Aaron. But then the question is, what was Jacob's original form? Was Jacob a formless entity to begin with?