Jacob and Smoke Monster
Ok, heres my theory.
Jacob and the Smoke Monster and enemies. The Smoke Monster can take form of any person if they have died to convince other people to do things. Now, We saw that Ben’s daughter was dead and the smoke monste took her form to convince Ben to obey Locke. (note that Locke could not go with Ben)
Locke was supposedly not dead until we saw in that big metal crate, his dead body. My theory is that since the Smoke Monster takes forms of dead people, it took form of Locke since he was actually dead. The smoke monster in Locke’s form used ben to kill Jacob.
Also, when I said “(note that Locke could not go with Ben) ” I meant that I don’t think the Smoke Monster can take two forms at once. Therefore, since the smoke monster was ben’s daughter at the time, it could not be Locke too. And so, “Locke” had to stay behind and wait for Ben. (though it was really the smoke monster)
That may or may not be the actual truth, but it just came to me and I wanted to share it. I hope it made sense!