Well, to make a long story short, FATE is a super computer created goddess that controls everything people do through subtle mind manipulations through devices called Records of Fate.  She uses her link ups through these 'save points' that you see scattered across the game world and anywhere on the world map to control and manipulate people so that the timeline she came from remains intact.  Those that try to fight her end up being destroyed and never allowed to be born since she has some time manipulation abilities.  The Records of Fate also send data back to her so that she can analyze it and apply whatever means she has to to make sure the timeline is maintained.  During the story someone got into her inner sanctum during a terrible storm, and used her downed defenses and the source of her dark power to heal a young boy.  That boy would accidentally lock the source of her power from her, and while she's still powerful without the aid of her magical source, she couldn't control the world that the boy came from after that.  Anyway, is that enough for ya or do I need to send the wiki page to ya?