I am your worst nightmare,
I am hated and feared by the most,
I am pain, i am suffer,
I brought you to the limits of your mind,
I am legend,
I have seen many of your kind dying,
Trying to make my core their,
I've been Flooded, but i'll never be
Their slave,
I am Forerunner,
But you must be Inheritor.
What am i? (it's not THAT difficult, but i put my heart in this riddle, so...enjoy!)