Scrapped Reclaimer

After the Human-Forerunner war the humans are left trapped on the Earth, de-evolved by the Forerunners. When the Forerunner-Flood war starts the Forerunners decided to prtotect the humans, Earth is converted into a prototype shield world in order to protect its inhabitants. However before the Forerunners can assign the mission to the guardians to watch over earth, they are betrayed