Players will be hard-pressed to find a more popular Mortal Kombat character than Sub-Zero, who even had his own spinoff game Mortal Kombat Mythologies: Sub-Zero. One of the few characters to appear in every game, Sub-Zero has a passionate fanbase who were excited to see him in the 2021 live-action movie.
Unfortunately, the Mortal Kombat film cast Sub-Zero as a villain and a henchman. While this may have been okay with audiences unfamiliar with the franchise, this character decision is mostly at odds with his characterization in the lore and story of the games: a staunch, if aloof, defender of Earthrealm. Beyond the violence and fatalities, there have been many examples throughout the series of Sub-Zero as a hero.
Sparing Sareena
One of the reasons for Sub-Zero's mischaracterizations could be because of the very first holder of the title: Bi-Han. Unlike his younger brother and successor, Kuai Liang, Bi-Han was more of a cold and ruthless warrior. His first loyalty was to the Lin Kuei clan and its goals, dutifully fulfilling them as the elder Sub-Zero.
Perhaps his only act of kindness was sparing the Netherrealm demon Sareena during the events of Mythologies: Sub-Zero. No specific reason was ever given, but Sareena's survival was essential in Sub-Zero defeating the sorcerer Quan Chi and reclaiming the amulet of Shinnok. Unfortunately, this heroic act did not save Bi-Han from his fate when he was killed by Scorpion and turned into something even more sinister and deadly.
Redeeming Bi-Han
The black-clad ninja Noob Saibot originally debuted in Mortal Kombat II as a secret opponent with no backstory. His subsequent appearances kept his story a mystery. It was not until Mortal Kombat: Deception that his true identity was revealed to be a resurrected Bi-Han. He reveled in his new powers and cut ties with his past life, including the new Sub-Zero, Kuai Liang.
In his Mortal Kombat 11 ending, Kuai Liang defeated the titan Kronika and attained power over time. He sifted through Bi-Han's history to redeem him, resulting in the brothers becoming joint Grandmasters of the reformed Lin Kuei in defense of Earthrealm. Since Liu Kang's story mode ending with a new history is likely canon, it is unknown if Bi-Han's history will repeat itself.
Joining The Justice League
Injustice 2 was the follow-up to Injustice: Gods Among Us and continued the story of Batman's resistance opposing Superman's regime. As NeatherRealm Studios also developed it, Sub-Zero and Raiden were included as downloadable guest fighters. Though Sub-Zero's appearance is not canon, it provides an exciting outcome when he defeated Brainiac in his arcade mode ending.
After Sub-Zero defeated Brainiac, Batman offered the Justice League assistance in getting him back to his universe, and in return, he trained their youngest members in combat. His membership in the Justice League was more solidified when magic accidentally freed the evil Superman and his followers from the Phantom Zone. The idea of Sub-Zero joining the Justice League is, pun intended, so cool.
Training The Special Forces
Even when Sub-Zero attained leadership of the Lin Kuei, he was not quick to proactively join the fight against the other realms. This uncertainty prompted Cassie Cage and her team to infiltrate the Lin Kuei temple in the arctic during the events of Mortal Kombat X. Sub-Zero and his clan took advantage of their inexperience and soundly defeated them.
The whole scenario was, in reality, a training exercise arranged by Sub-Zero and the team's commander, Johnny Cage. Sub-Zero chastised the team for their lack of coordination but praised their potential. The training paid off when he fought alongside during the climax of the game against Outworld invaders and commended the team for their bravery.
Granting Sanctuary To Sareena
Mythologies: Sub-Zero was not the last time Sarenna played a role in the story. She reappeared playable in Mortal Kombat: Tournament Edition, the Game Boy Advance companion title to Mortal Kombat: Deadly Alliance. It retconned her fate from Mythologies: Sub-Zero, where she did not die but instead lost her human form and eventually made her way into Outworld.
She met Kuai Liang, who recognized her from Bi-Han's stories and experiences. In gratitude for her helping his brother, Kuai Liang offered her sanctuary with the Lin Kuei at their temple. It was a considerable risk given Sareena's heritage, but his faith was not misplaced; Sareena stayed true to her world and vowed to protect the clan.
Freeing Smoke
Like Noob Saibot, Smoke first appeared in Mortal Kombat II as a secret opponent. Mortal Kombat 3 expanded him further by making him playable and a friend of Sub-Zero that fell victim to Lin Kuei's cyber initiative. When Sub-Zero escaped, Smoke was one of the cyborgs sent to terminate him.
Rather than destroying his friend, Sub-Zero sensed the human soul trapped in the machine and helped Smoke break free of the programming. He did this again later during the events of the highly contentious Mortal Kombat: Armageddon when he freed Smoke from the influence of Noob Saibot. Sub-Zero's compassion and friendship with Smoke further proved how he was a good soul at heart, contrary to Lin Kuei's forbidding of attachments.
Freeing And Accepting Cyrax
As a reboot of the series with a new timeline, Mortal Kombat (2011) expanded on its characters in ways the original arcade games could not. Cyrax is one of these characters, where his tragedy of the man trapped in the machine was fleshed out. From the start, he was outspoken against the cyber initiative and left the clan after advice from Raiden.
Sadly, he was captured and converted, and he continued to serve as Sektor's lackey. Cyrax was eventually freed by Sub-Zero in Mortal Kombat 11 and, horrified by what he became, sacrificed himself to destroy Sektor's operations. Cyrax begged Sub-Zero not to bring him back as a machine, and Sub-Zero nobly declared that regardless of whether he was a man or machine, Cyrax always had a place in the Lin Kuei.
Sparing His Opponent In The Outworld Tournament
The classic Mortal Kombat arcade games relied on character biographies and endings to tell their stories. These storytelling methods established the second Sub-Zero and revealed that he spared an opponent during the events of Mortal Kombat II. Sub-Zero's humanity was thus demonstrated and immediately set him apart from the first Sub-Zero who entered the first tournament to kill the manipulative sorcerer Shang Tsung.
This act of kindness was not unnoticed by Scorpion, who realized this was not the same Sub-Zero he killed in the first tournament. During the events of Mortal Kombat 3, when Shao Khan invaded Earthrealm, Scorpion allied with the forces of good to protect Sub-Zero. It was not the last time the two rivals fought on the same side and put aside their differences.
Reforming The Lin Kuei To Protect Earthrealm
In most games, the Lin Kuei was a ruthless clan of assassins that served the highest bidder, regardless of their alignment. They worked for their self-interests, even if it meant endangering Earthrealm, as demonstrated in Mythologies: Sub-Zero and Mortal Kombat (2011). The cyber initiative and allying with Shao Khan further proved Lin Kuei's descent.
In the original and rebooted timelines, when Sub-Zero defeated Sektor and became its new Grandmaster, his changes to the Lin Kuei were striking. He relocated the clan to the arctic and turned them from ruthless mercenaries into honorable warriors. Despite their reclusive nature, the new Lin Kuei were invaluable allies to other factions such as the Special Forces, Shaolin, and Shirai Ryu for the defense of Earthrealm.
Making Peace With Scorpion
The feud between Sub-Zero and Scorpion is legendary within Mortal Kombat. The two always come into conflict together, primarily because of the hatred between the Lin Kui and Shirai Ryu clans. This rivalry was essential to the franchise's marketing and even extended to spinoff material such as the animated Mortal Kombat films and the 2021 Mortal Kombat movie.
This all changed in Mortal Kombat X when Sub-Zero extended an olive branch to Scorpion and made peace after the truth of Lin Kuei's complicity with Quan Chi in killing Scorpion's family was revealed. This partnership got a chance to shine in Mortal Kombat 11 when Scorpion aided Sub-Zero in taking down Sektor and when the two fought together in the game's climax.