The Woman Was The First Jacob And The First MIB Put Together by the goat man

The Woman was a member of the first arrivals to the Island before our AD time period. The antiquities that existed on the Island were built by her people. The Temple and such were not shown, but still existed when the twins mother and her people arrived on the Island. She unwittingly stumbled upon the true meaning of the Island and was transformed into the first Jacob/MIB guardian being to the Island. Her form is actually a reflection of this dead woman.

There would be no bearing of children or leaving the Island for this woman. When Jacob and MIB's mother arrived with her people after the first civilization to the Island died off she merely wanted this woman's child for companionship in her lonely existence. But, on the birth of Jacob's twin, the Woman saw the very first loophole to leave the Island. She would pass on her role as protector to Jacob. And use MIB to kill herself. Now there was no way for MIB to harm Jacob or Jacob to harm the MIB. The loophole was closed supposedly for all time by the death of the Woman. But, MIB found a new loophole in our present time period. I know that it appears that Jacob's brother died by his hand. But, I've got to believe that maybe they both were already imparted with whatever lies within the Light as babies by the Woman. She may have sent them through the Light as a sort of baptism. Maybe they have no knowledge of this because they were to young to realize what was done to them. Quite possibly MIB suffered the same fate as Sayid by being exposed to the Light for a second time(as in his being dunked in the pool in the Temple). His reintroduction to the Light produced his Smoke Monster abilities that were possessed by the Woman. It would appear that Jacob was left by the Woman to be the first protector of the Island, and MIB was actually the first candidate.