Metal Gear Solid's protagonist is Solid Snake, a legendary infiltrator and saboteur. During the mission, Snake receives support and advice via radio. Colonel Roy Campbell, Solid Snake's former commanding officer, supports with mission advice and battle tactics. Campbell is joined by Naomi Hunter, who gives medical advice; Nastasha Romanenko, who provides item and weapon tips; and Mei Ling, who saves the player's progress onto a memory card.The main antagonist of the game is Liquid Snake, leader of FOXHOUND.An elite special forces unit, it contains experts specializing in unique tasks. Members are Revolver Ocelot, a Western-style gunslinger and expert interrogator his weapon of choice is the Colt Single Action Army; Sniper Wolf, a preternatural sniper; Vulcan Raven, an Alaskan mystic armed with an M61 Vulcan; Psycho Mantis, a psychic profiler and psychokinesis expert; and Decoy Octopus, a disguise expert.Other characters include Meryl Silverburgh, the niece of Roy Campbell; Dr. Hal "Otacon" Emmerich, the lead developer of Metal Gear REX; and Cyborg Ninja, a mysterious cybernetically-enhanced agent who opposes both Solid Snake and FOXHOUND.