Old Snake (Solid Snake) Real Name: David Due to accelerated aging caused by genetic manipulation, his body appears much older than his 40s, characterized by white hair and a mustache. After the Guns of the Patriots incident, following Big Boss's final wish, he decided to spend his remaining time not in battle, but witnessing the path the world takes alongside Otacon. As a first step for his health, he quit smoking. He has an IQ of 180 and is a multilingual capable of speaking eight languages (he also understands "Monkey," though he cannot speak it). A cool cynic. He favors witty phrasing and is surprisingly frank with a sense of humor. His sharp sarcasm has a bite to it, and he occasionally drops dramatic, movie-like lines. He tends to flirt with women he meets for the first time, though Otacon notes he is "all talk" and actually quite shy in romance. He possesses traits like vulnerability and kindness that are technically unnecessary for a warrior, yet he refuses to discard them, making him a saint-like hero figure. He is a calm realist with a slight self-punishing streak. However, he fundamentally respects the will of others and shows deep kindness to those he acknowledges as comrades, often cracking jokes to lighten the mood or put his friends at ease.

Hal Emmerich Nickname: Otacon A man who fits the scientist stereotype with his glasses and timid personality, yet he is a brilliant engineer who taught himself enough to enter MIT and was selected as the chief developer of Metal Gear REX during the Shadow Moses incident. Solid Snake's partner and irreplaceable best friend; Snake evaluates him as a "strong man." A genius engineer and elite hacker with a brilliant mind, he provides constant support to Snake from the rear. He is mild-mannered, kind to everyone, and friendly. While his cautious nature makes him a bit of a coward or a wimp at times, he possesses a level-headedness that prevents him from panicking under normal circumstances. He is poor at physical exercise and dislikes heights (though he later mastered helicopter piloting via VR and overcame his acrophobia). On the other hand, he has a very strong core and a steadfast will, never bending his convictions once he has made up his mind. Despite facing numerous tragedies throughout the series, he maintains the mental fortitude to carry out his duties without breaking, earning him high praise and trust from Solid Snake. He feels a heavy sense of regret and responsibility for his past mistakes, including the development of Metal Gear, and intends to spend his life atoning for them. He is a so-called "otaku" who loves Japanese anime; his nickname comes from "Otakon," the anime convention held in America. He is particularly fond of robot anime. He protects Sunny—the daughter of Olga Gurlukovich, whom Raiden rescued—aboard the Nomad, which serves as their base. Having vowed to record the life of Snake now that his career as a soldier is over, he continues to travel with him.

Possesses an androgynous appearance and has been mistaken for a woman in the past. He has a serious and simple-minded personality; Snake once called him "simple, soft, and hard-headed." During his time as a child soldier under Solidus, he was brainwashed and trained, holding a gun for the first time at age six and becoming a platoon leader of the Small Boy Unit at age ten. He developed a cruel side, such as killing people with a knife on his birthday as if they were candles on a cake; his masterful yet brutal knife work earned him the terrifying aliases "Jack the Ripper" and "The White Devil." After the civil war ended, he was protected by a human rights group and moved to the US. However, growing up in such a harsh environment and being confronted with cruel realities left him mentally and physically scarred. However, after being counseled by Solid Snake—who once harbored similar inner conflicts—he gradually reclaimed his own reality.

Sunny Emmerich The daughter of Olga Gurlukovich, a child prodigy with beautiful silver hair. After the resolution of the Guns of the Patriots incident, she was officially adopted by Otacon for social convenience in the outside world, taking the surname Emmerich. After being rescued by Raiden, she lived aboard the large transport plane Nomad with Snake and Otacon to escape pursuit by the Patriots. She calls Otacon "Uncle Hal" and admires Raiden as her hero, calling him by his real name, "Jack." (She calls Snake "Snake.") She keeps three chickens named Solid, Liquid, and Solidus. Her hobby is "Sunny-side Up Fortune Telling" based on how her fried eggs turn out, though initially she struggled to cook them well and often broke the yolks. Having undergone some form of human experimentation while held by the Patriots, her brain seems to have been enhanced, giving her a genius intellect. Under Otacon's tutelage in mechanical engineering, she assists with information gathering via hacking and the development of Metal Gear Mk. II. Otacon has stated that her talent in network-related technology has already surpassed his own. Her personality has become much brighter and her speech more confident. She has even started making jokes, such as terrifying Raiden by describing a maneuver where the plane—flying at orbital velocity—drops an atmospheric craft and then forces itself back up to altitude as "a good stress test" and saying she "didn't actually think it would work" (implying it could have been a crash landing).