Liquid Snake

Liquid Snake (リキッド・スネーク) (commonly referred to as Liquid) was Solid Snake's twin brother/genetic duplicate and the Field Commander of FOXHOUND during the Shadow Moses Incident. He was the "son" of Big Boss, created in the Les Enfants Terribles project, along with his "brothers" Solid Snake and Solidus Snake. Liquid Snake believed himself to be inferior to Solid Snake, as he was told that he was the recipient of Big Boss' recessive genes. Believing this, Liquid held a strong resentment towards Solid Snake, who supposedly inherited the better genetics, and wished to defeat him in combat and reclaim what he felt was his birthright, thus proving his superiority.

Liquid was 182 cm tall, had an IQ of 180, and spoke seven languages fluently. He was almost an exact double of Solid Snake in terms of appearance, with the only distinguishable feature being his darker skin tone and hairstyle (type and color, though it should be noted that Solid Snake, when he was "summoned" from Alaska, originally had the same hairstyle as Liquid, but he cut his hair just prior to being sent to Shadow Moses Island so that he "won't be mistaken for Liquid."). He also had a tattoo on his left arm, which resembled the Rod of Asclepius, but with a sword in its place. He also had a British accent.

Early Life
Liquid was raised in the UK shortly after birth and was the youngest person to serve in the Special Air Service, at the age of 18. His real name was also heavily classified to the extent that even someone among the highest levels of the Military chain of command is forbidden to know about it. During the Gulf War in Iraq, he was assigned to a Special Air Service unit to track down and destroy mobile Scud missiles. In truth, he infiltrated the Middle East as a sleeper agent for the British SIS, but was taken prisoner by Iraqi forces and held captive as a prisoner of war until 1994, when he was rescued by the U.S. Government. Liquid Snake joined FOXHOUND in the year 2000, after Solid Snake and Colonel Campbell had already retired from the unit. After Liquid joined, he became the Field Commander of FOXHOUND.

In 2005, Liquid Snake along with FOXHOUND members Decoy Octopus, Psycho Mantis, Sniper Wolf, Vulcan Raven, Revolver Ocelot, and the Genome Army, formed a terrorist group called the Sons of Big Boss. The terrorists seized control of Shadow Moses Island and the nuclear equipped Metal Gear REX, taking the DARPA Chief Donald Anderson and ArmsTech President Kenneth Baker as hostages. Liquid then demanded the preserved remains of Big Boss in order to produce a cure for the genetic defects of the Genome Army. Basing himself in the Shadow Moses facility, and supported by FOXHOUND, the Genome Army, and Metal Gear's nuclear capabilities, Liquid intended to recreate Outer Heaven. With these vast resources at his command, Liquid would drag the world into the Third World War, wanting to fulfil Big Boss' dream of a world which always had a place for soldiers.

During the course of Solid Snake's mission to eliminate the nuclear threat, he was confronted by Liquid on several occasions. Initially, Liquid attacked Snake with a Hind D attack helicopter as he crossed the Communications Towers, the Russian gunship menacing Snake several times before a final showdown on the roof of one tower; the Hind eventually went down in flames due to Stinger missiles fired by Snake. He survived (a parachute is visible on a tree in the Snowfield of the base, though a Codec call confirms he couldn't possibly have used it and placed it there after crashing to taunt Snake with his survival) and then tricked Snake into activating REX with Kenneth Baker's PAL card by posing as McDonell Miller (Liquid had him killed earlier) during codec calls.

The entire final act of the Shadow Moses Island incident was a series of battles between Snake and Liquid. First, Liquid piloted Metal Gear REX and attacked Snake, but, with the help of Gray Fox, Snake destroyed Metal Gear. Then, Liquid and Snake battled bare-handed atop the ruins of Metal Gear, attempting to fling each other from the top of the ruined bipedal tank to the ground far below. While it seemed Snake was victorious in this struggle, Liquid, still able to fire a FAMAS one-handed, pursued him as he tried to escape from the impending nuclear strike. Ultimately, Liquid fell victim to the genetically engineered FOXDIE virus, just outside the facility.

A final conversation between Ocelot and George Sears (Solidus Snake) reveals that Liquid was in fact the superior clone and Solid Snake the inferior one.

Liquid Snake's influence did not stop with his death. Liquid managed to posthumously take control of former ally Revolver Ocelot (via the transplant of the right arm that once belonged to Liquid) during Ocelot's heist of the Metal Gear RAY prototype in 2007. Two years later, he anonymously tipped off Solid Snake and Otacon about the events unfolding at the Big Shell, as he knew he could only take full control of Ocelot in Snake's presence. Following Arsenal Gear's take-off, he stole RAY and escaped in search of the Patriots.

In addition, Liquid's corpse was stolen by Snake after the Tanker Incident in an attempt to fake his own death. After examining the body, Rosemary confirmed that the DNA matched that of Solid Snake, seemingly confirming his death to Raiden.

In 2014, Liquid Snake had seemingly taken full control of Revolver Ocelot, creating the new entity: "Liquid Ocelot". In reality, Ocelot had replaced Liquid's arm with a cybernetic one at some point between the Manhattan Incident and Liquid's Insurrection and from then on he had merely pretended to be Liquid to trick the Patriots. Before his death, Ocelot referred to himself to Solid Snake as "Liquid's doppelgänger". Big Boss later explained to Snake that Ocelot was able to recreate Liquid's consciousness using nanomachines and hypnotherapy.

Meanwhile, Liquid's corpse was put to further use; various body parts of his were used in the process of rebuilding Big Boss' damaged body.

Personality and Characteristics
Liquid displays an arrogant and loud attitude in stark contrast to Solid Snake, who is more calm and collected.

He was an especially adept pilot; as shown when he was flying a Hind D during a blizzard as a dangerous decision, especially in combat against two F-16's, as well as pilot it from within the weapons operator's cockpit. He would later use the same chopper to combat Snake.

Liquid also displayed superhuman endurance, surviving a helicopter crash, repeated hits with surface-to-air missiles, sitting right on top of an explosion so powerful it knocks Snake out from the other side of the room, falling off Metal Gear REX, repeated hits from a .50 caliber heavy machine gun and a car crash; he is still standing immediately before he finally succumbs to FOXDIE.

He was incredibly bitter towards Big Boss and Solid Snake. Although his hatred for them knows no bounds, he was also driven by a sense of connection to his twin brother. His main drive was the belief that he bears all of Big Boss's recessive genes, and that he was born knowing that his brother was superior. He is driven to surpass his genetic destiny, and in essence, his father. However, he never learned the truth that it was in fact he that gained the superior genes, while Solid Snake was the inferior. Therefore, in an ironic twist, it turns out that Snake did what Liquid had set out to do all along, with neither of them ever knowing (although it's possible that Liquid did manage to find out about his true inheritance after taking control of Ocelot, due to his comments about how he has access to Ocelot's memories).

Trivia

 * According to the Cardboard Box trophy in Super Smash Bros. Brawl, Liquid is just as fond of cardboard boxes as his brother.
 * Liquid is the only Snake that has not worn an eyepatch (or a similar device).
 * AbbyShot Clothiers, a company that creates media-inspired and video game clothing, created a trench coat similar to the one that Liquid wears. It is priced at $400 CAD, $343.14 USD, and £223.44.
 * When outside the control room of Metal Gear REX before Snake loses the PAL Card, the player can contact Liquid, who will still answer disguised as Master Miller, even though Liquid will appear to be sharing a conversation with Ocelot if the player looks at the control room in first person view.
 * In the original plot for Metal Gear Solid 2, Liquid was supposed to have faked his death from FOXDIE. He was also going to be the actual main villain of the game. However, this, along with most of the original plot, was scrapped.
 * Killing enough human enemies in Metal Gear Solid 4 will cause Old Snake to have a flashback of what Liquid told him at the end of Metal Gear Solid ("You enjoy all the killing, that's why!"). The shock from this episode causes Snake to throw up and his Psyche Gauge lowers drastically.
 * In MGS4, during the opening stage of the final battle with Liquid Ocelot, images of Liquid from MGS1 flash on the screen, and the "Encounter" music from MGS1 is played. Liquid Ocelot's attack patterns in this stage are similar to the ones Liquid Snake used in the fistfight on REX. The pre-fight cutscene also bears some resemblance to The Twin Snakes post-battle cutscene with Liquid.
 * During the unveiling of Metal Gear Solid: Peace Walker at the 2009 Tokyo Game Show, Hideo Kojima announced that Liquid will appear in the game. He also announced that the game will reveal exactly what made Liquid the way he was. However Liquid was two years old during the events of Peace Walker. Therefore, how he will appear is unknown.
 * Liquid Snake and Zero share many similarities. Liquid was the commander of FOXHOUND in Metal Gear Solid while Zero was the commander of FOX 41 years prior. Liquid considers himself enemies of his brother Solid Snake and their father Big Boss while Zero was friends then enemies with Big Boss. They both have an ego (with Liquid, his ego is more known while Zero developed his ego later in his life). Lastly, both Liquid Snake and Zero share the same voice actor (Banjo Ginja) in the Japanese version of the Metal Gear series.
 * In Metal Gear Solid: Portable Ops, Liquid is seen in a prophetic vision of Elisa and Ursula, revealing that Liquid will bring the world to ruin and Snake will ultimately save it.