I privately think this may be a story told to the vaults systems as having happened. Since this is not stated I imagine some sort of story that proves robots, lets say the Vex, were originally created by man. a "hive-mind" and with the purpose benefit/defend life. Some entity, bent on destruction, *cough* Oryx *cough* may then have tried to use a "weapon of sorrow" against these robots in the attempt to stop them, and became connected to the "hive". The robots controlled by logic that is to defend life, continuing said logic began to inexorably unravel this entity. The entity attempted to flee this telepathic intrusion by travelling to a place beyond the robots reach. Failing to find such refuge through distance the entity began to work through paradox. Defining itself to be either light or dark - whichever came first is its last defense. Seeking to build platforms in the hopes of rebuilding itself this entity describes a war between light and dark, only to be thwarted at each stage of the war by a strange robot identical in look to the first and only robot consumed by the entity. This stranger to the entity and its servants continues to thwart the entity with the inherit flaw within its last stand, cleansing the machinations of the entity and giving the servants life... End transmission.