Outriders Secret Mission & Legendary Chest Location

Outriders Secret Mission & Legendary Chest Location – Outriders Secret Mission & Legendary Chest Location. This legendary chest is found in the canyon of the grand obelisk and you need to find 3 secret keystones to unlock a hidden mission. The mission once started is to simply open your legendary chest.
Good content dude do you know the funny thing is is I activated all those keys but I never went back to the door and open it. hehehe