Sub-Zero is the name given to two video game characters from the Mortal Kombat series. The older Sub-Zero first appeared in the first Mortal Kombat game, being replaced by his younger brother in Mortal Kombat II and the subsequent games. In Ultimate Mortal Kombat 3 and most versions of Mortal Kombat Trilogy, both the elder and younger Sub-Zero appear as playable characters. Sub-Zero also appears in many other Mortal Kombat media works such as the Mortal Kombat live action film series and animated series.
Being brothers, both of them were born in Earthrealm, and are blue-garbed assassins that descended from Cryomancers, an ancient race of people possessing the ability to generate and control the powers of ice, which gives Sub-Zero the innate ability to control ice in many forms. Sub-Zero has received positive reception and was featured on multiple lists of the best video game ninja characters, also inspiring the character of Glacier in World Championship Wrestling.
The oldest of the two brothers who takes the name Sub-Zero, called Bi-Han (Chinese: 避寒; pinyin: Bìhán),was introduced in the first Mortal Kombat game where he participates in the titular tournament as he was ordered by the Lin Kuei to kill the host Shang Tsung and take his treasure. He fails to accomplish his mission, and is killed by the specter Scorpion, who sought to avenge his own death.
In the direct sequel Mortal Kombat II, Bi-Han's place is taken by his brother Kuai Liang (Chinese: 快涼; pinyin: Kuàiliáng). Upon his brother's death in the first tournament and the survival of Shang Tsung, Kuai Liang is sent by the Lin Kuei to complete his brother's unfinished task. In Mortal Kombat 3, the younger Sub-Zero escapes from the Lin Kuei who wanted to transform their warriors into cyborgs. They program three cyborg assassins to hunt and terminate Sub-Zero, who by this time had received a vision from Raiden and agreed to join the rebellion against a new threat.
In Ultimate Mortal Kombat 3 and Mortal Kombat Trilogy, "Classic Sub-Zero" also appears as a playable character. His biography states that although he was believed to have died after the first Mortal Kombat, he returned to try again and assassinate Shang Tsung. In Mortal Kombat Mythologies: Sub-Zero, which serves as a prequel to the first Mortal Kombat, sorcerer Quan Chi hires the Lin Kuei to find an ancient amulet. After the first Sub-Zero delivers the amulet to Quan Chi, he is sent back to the Netherrealm by Raiden upon learning it is the key to releasing the god Shinnok. Sub-Zero regains the amulet while fighting Shinnok and returns it to Raiden.
In Mortal Kombat 4, Raiden once again summons the younger Sub-Zero to assist in the defense of Earthrealm against the former Elder God Shinnok.In the meantime, Sub-Zero fights Scorpion, who was told by Quan Chi that the Lin Kuei killed his family, but he leaves him upon discovering Quan Chi was the actual person responsible. In Deadly Alliance, Sub-Zero defeats Sektor in a fight for leadership of the Lin Kuei Clan. He also meets Frost, his apprentice, and takes her to fight alongside Earthrealm's warriors against the alliance of Shang Tsung and Quan Chi.
In Mortal Kombat: Deception, Sub-Zero joins Shujinko's group to defeat the new threat in Onaga. He also confronts his corrupted older brother, now the undead Noob Saibot, across these game. In both Deadly Alliance and Mortal Kombat: Unchained, Sub-Zero comes to encounter Frost for the Lin Kuei's leadership, but he remains victorious.
In Mortal Kombat: Shaolin Monks, which reprises the events from Mortal Kombat II, Sub-Zero first appears as a boss character, but then allies with the protagonists Liu Kang and Kung Lao for a short time during the search of his older brother.
In Armageddon's Konquest mode, Sub-Zero faces the warrior Taven, who invaded the Lin Kuei Palace. Both eventually decide to ally to stop the invading Noob Saibot and Smoke. After the invaders' defeat, Sub-Zero stays with the unconscious Noob Saibot to find a way to save him.
He is also playable in the crossover title Mortal Kombat vs. DC Universe; in the storyline, Sub-Zero is involved in a war between the titular fictional universes and is the protagonist for one chapter of the story mode. Ed Boon notes that Sub-Zero's counterpart from DC Comics is Batman as both are "dark, mysterious, brooding characters."
Both incarnations of Sub-Zero appear in the 2011 Mortal Kombat game. While Bi-Han is killed by Scorpion and becomes Noob Saibot, Kuai Liang's fate changes in the first tournament due to Raiden's interference; the timeline is altered and Sub-Zero is captured and turned into a cyborg instead of Smoke. He is able to regain his mind and joins Raiden's warriors to stop Shao Kahn. However, he is killed by Kahn's wife, Sindel, and he remains enslaved by Quan Chi in the Netherrealm