Staff Sergeant Rainer was one of the Marines in charge of perimeter defense of Central Station during the Battle of Libery City. His men were ordered to demolish the lower foundation of the ONYX building in order to block Ceph mortar fire from hitting Central Station. When Alcatraz arrives in the area, he orders him to reset the breakers on the explosives, as the detonators are not setting them off. Once Alcatraz re-activates them, Rainer orders him to vacate the building. One of his men, Torres, attempts to detonate the explosives, but is overrun by Ceph before he can. Rainer orders someone to retrieve the detonator and detonate the explosives, which Alcatraz does. When Alcatraz returns, Rainer tells him to head inside to meet with Barclay.