Jacob/Mib
In the S5 finally, the Incident, we see Jacob and MiB discussing the Black Rock’s arrival and the Human condition. This being the Good vs Evil, White/Black argument. My theory is not about the decision of man to do good or ill, but in Jacob and Mib. We know now that they are the yin and yang of each other, or different sides of the same coin. In their discussion Jacob says “everything until then is progress” Mib says “it all ends the same”. There have been many theories on the destiny vs free will. Yes I agree that this was the meaning behind the conversation, but there is something much more to it. About the 2 of them and more of their purpose. It’s the end of the show guys, one more hurrah and they are going to tie it all togther and show us what has been right under our noses right from the start. They are finally going to show us what the picture looks like of the puzzle we have been putting together for 5 years. We finally get the box, not just the pieces. So I looked back into the seasons and found some really interesting, points.
Thinking back to Season 1, Locke encounters, what we believe to be smokie, while out hunting boar. Although we never actually see Smokie until the end of the season. What Locke says after he returns and is asked about what happens is “I looked into the eye of this Island and what I saw was beautiful”. This does not sound like what we know as Smokie. We know it to be a “monster”. I have never thought that Locke saw Smokie the first time, because when he sees Smokie at the end of S1, whilst being dragged through the jungle and almost into the hole in the ground, Locke looks horrified! Not like like he’s looking at and old friend or someone he’s met before. I think that Locke saw Jacob in his ethereal form the first time. That is why he said it was beautiful, Maybe a flashing “white” smoke. That would look rather beautiful. Very “heavenly” looking I guess. I think Smokie is MiB in ethereal form, made to not look so “beautiful”. Not to stand in awe but in fear of it. Ying/Yang, Light/Dark, Baked/Fried, thin crust…etc.
During Jacob and Mib’s conversation on the beach, many pose the light/dark again. So I tried to look at a little differently. They were discussing the free will of men, but I think more than that they were discussing what they are going to do about it. I think that MiB saying “I don’t have to ask” was not in reference to knowing Jacob brought them there, he alredy knew that. It meant he could just smite them all. Jacob seemed more of a non-judgemental character, like he is willing to give them a chance. Where as MiB, seemed to judge them instanly without ever seeing them. (yes Light/Dark reference again) Which, if we go by what we know of Smokie now, we are told that it is some kind of judge, sounding very much like MiB . If there is balance in LOST as we have seen so far, Black/White, would it be outrageous to think there are 2 smoke monsters one black, one white? This would explain Locke’s look of shock, in the season 1 finally. Seeing a nice bright white, shining or flashing smoke at first, then seeing a dark ominous roaring black one that drags you through the jungle and nearly to your death into a hole. I would have 2 different reactions.
There is also another reference while Jin is flashing through time made by Robert, from Danielle’s party, during the conversation right before he is shot in the head. He says it is a security system to protect the temple. Well MiB sounds very protective, during the conversation, almost like he wants to keep the people out. Where as Jacob sounds inviting like he wants people to learn something. (knowledge from the temple perhaps) Such as the Other’s. Are they worthy?Do their names make the list.
I believe that it is a combination effort between Jacob an Mib to determine who stays and who goes/dies. One Judges the other Reviews the decision. A sort of checks and balance system. We know there is a set of “rules” that must be abided by, but we don’t know what they are yet. Rules for time travel, for killing each other or each others offspring, and for coming back to the island. And it seems that Jacob and Mib are bound by a set of rules as well. Therefore, I think they are not, the God/Satan, because if they were they would just make their own rules. Jacob and Mib still answer to someone, THEY could be the God/Satan comparison, but I am sure that Jacob/Mib are not the top of the Food chain, they still have to follow the rules, and are subject to death like anyone else.
Lastly, I would like to comment on MiB using Lockes body as a proxy to bend the rules. I believe Jacob is going to do the exact same thing using Locke from the crate, to come back for the fight. Also, going back to S1, in Claire’s dream Locke has one black and one white eye. I think this is what it was symbolizing. Quite possibly seeing a Jacob in Locke-form. I think we see Jacob going back and interacting with all the Losites in their past, because he knew he would the outcome of events. Just as MiB manipulated events to get there in Locke-form, even saying “you have no idea what I have gone through to be here”. Jacob has been manipulating events as well, to make Jack, Kate, Sawyer all play their part to detonate the nuke. If Faraday is correct and it will reset everything back the way it was, then Jacob is back alive and Mib is right back to being a hater. Something will go a miss, it is LOST after all. What? no idea, but I do have some ideas in many other areas. Hope this stirs some thoughts.

I think MIB is House.
No way House is the man. House is like Jacob, God hates both of them because they are too good.