The first time Keystone Company are seen is while making your way to the North Tower in Twin Falls where their corpses, and Spinner Pods are strewn along the bridge. It is believed that Keystone was there to protect Twin Falls, and during the ground assault told the majority of the civilian population to hide in a train tunnel. When the Chimera attacked all the population in the train tunnel were infected and the few survivors, with the help of Sentinel Team Lima, tried to stop the Chimeran forces and activate the tower.Sadly,they all died trying.
At the beginning of the Leviathan boss fight in Chicago, Illinois Keystone are seen again this time following the Leviathan in a U/AV-17 Hawk. They request permission to fight it, but are denied by Major Blake who tells them to retreat. As they try to escape the Leviathan hits their VTOL and sends them, in a ball of flames, into the side of a building which instantly kills them.
- Keystone Six (Deceased)
- Even though Keystone Company collided into the building in Chicago, if you look there just after the Leviathan tries to eat you for the first time there is no sign of damage to the wall or any sign of a VTOL.
- Keystone Company could have been named after a SRPA base in Keystone, South Dakota that was seen in Metastasis.