Exact quote
"Unacceptable! Unacceptable! That is absolutely unacceptable! Protocol dictates action! I see now that helping you was wrong! You are a child of my makers, inheritors of all they left behind. You are Forerunner, but this ring... is mine!"
Forgot all about this line from halo 3, thanks for jogging my memory
But it does give credit to the MC is Forerunner theory