the story so far!!
ok this is my first stab at a theory. ben has been working with MIB somewhat unknowingly, he led locke to the cabin to see Jacob which ended up being mib in christians form. from there on in lock is a believer in the island as flocke said locke was stupid enough to believe the island wanted him there, stupid enough to go back to the island. this brings eloise into play she got them back to the island meening she has choosen mibs side the agument between her and widmore was whos side to choose whidmore chose jacobs. remember the chat on the beach they come they fight but they fight for each side MIB or jacob, this has been the battle ever since the loop hole was john locke who believed in the island but unknowingly worked for MIB jack also unwitingly encouraged them all to go back including lockes body which mib knew he could take.
this is sketchy

Whoa, yeah, pretty much.