In the for finale season 5, Ilana (and her company: Bram, Lapidus, etc) encounter "Jacob's" cabin. As they approach, one of the members of the company (I beleive it was Bram, but I cannot remember) points out that the ring of ashes surrounding the cabin has been broken.
Now, I am of the opinion that every person we've seen on the island who shouldn't be there (like Jack's father, Mr. Eko's brother, random appearances of Walt, etc) is a manifestation of Jacob's rival, a.k.a the "Bad Twin."
I believe Jacob's rival, manifested as Jack's father, convinces Claire to leave Miles and Sawyer for whatever reason, follow him to Jacob's cabin, and make a gap in the ashes for him so he can enter the cabin (and later tell John Locke he is speaking for Jacob, setting everything into motion).
Now, I am of the opinion that every person we've seen on the island who shouldn't be there (like Jack's father, Mr. Eko's brother, random appearances of Walt, etc) is a manifestation of Jacob's rival, a.k.a the "Bad Twin."
I believe Jacob's rival, manifested as Jack's father, convinces Claire to leave Miles and Sawyer for whatever reason, follow him to Jacob's cabin, and make a gap in the ashes for him so he can enter the cabin (and later tell John Locke he is speaking for Jacob, setting everything into motion).
