In 2014, Vamp had joined with Liquid Ocelot, becoming one of his mercenaries, and also working closely with Laughing Octopus. He was first spotted by Solid Snake when he traveled to South America to rescue Naomi. After tracking Naomi, Snake spotted Vamp along with Naomi boarding a helicopter, and Snake shot Vamp once more in the head. Vamp took the shot, then stopped and commented that it was "time for his nap," before collapsing. Vamp rose to life once again moments later, surprising Snake. Shortly after, still in South America, Vamp fought with Raiden and mortally wounded him. After Snake rescued Naomi, she revealed the truth behind Vamp's regenerative capabilities, saying that, in a sense, he was "her monster."
Later, when Liquid Ocelot headed to Shadow Moses to obtain Metal Gear REX's railgun for his own ends, Liquid told Vamp to stay behind, as he knew Snake would eventually come to stop them. When Snake finally arrived, Vamp challenged him. After seemingly "killing" him several times, with Vamp simply collapsing only to rise again moments later, Snake injected Vamp with a drug that repressed his nanomachines, thus making him "mortal" again. Raiden appeared to eliminate several Suicide GEKKOs, before Vamp challenged Raiden to finally finish him. As Otacon attempted to revive Metal Gear REX, Snake held off the Gekkos while Vamp and Raiden fought on top of REX with their knives.
After Vamp incapacitated Raiden, he reached for Raiden's sword, only to have Raiden gain the upper hand, stabbing him in the stomach and finally bring Vamp's life to an end. Vamp fell from REX's head onto the ground below, where Naomi arrived and gave him a syringe that shut off his nanomachines which let him die of his injuries once and for all.
