endgame/ possible spoiler

as i wrote possible spoiler here.I think we can safely say jacob brought the losties to the island for a purpose.That purpose i think is that they will be the keepers of the island now that jacob is gone.I believe that jacob is indeed dead and that he always knew that he was going to die at the hands of his island rival.His rival was thirsty for his death and jacob always knew that eventually he would find his LOOPHOLE and kill him.The fact that the two island rivals are seen as black and white and that line that richard says in latin that jacob is the 1 to keep us safe and to protect us leads to me to believe the opposite is true for our friend in black.He is war and pestilence the opposite to jacob.In the last season i believe we will see jack and co. do battle in some way with the man in black and when all is done they will guard or protect the island like the others do now.people will say what about locke,my belief is that he was used the whole time he was on the island just as he was during his whole life before arriving on the island.I believe jack is and always was the main man for jacob.let me what u think.thanks