The part of the ego that assumes that the events of your life are pieces of an extended narrative, with you as the focal point. You may assume that true love is out there for you. Or that there's some sort of battle for justice you must fight. Or even just that it is your lot in life to spiral into a pit of hurt and despair. Anything motivated partially by some sort of narrative precedence is a case of narrative ego. Is probably brought about by watching too much television/reading too many novels.
"I believe that it is my job to right the wrongs that plague this city"
"You must have quite a narrative ego!"