Sareena is a demon of the Netherealm that first appeared in the Mortal Kombat spin-off Mortal Kombat Mythologies: Sub-Zero as a boss. She would later make her first playable appearance in Mortal Kombat: Tournament Edition on the Game Boy Advance and a later appearance in Mortal Kombat: Armageddon.
In the storyline of Mortal Kombat Mythologies, Sareena is first introduced as an assassin working for the sorcerer Quan Chi. She was tasked with eliminating Sub-Zero before he reached her employer. She, along with her allies Kia and Jataaka, engaged their target, but were all defeated. However, Sub-Zero chose to spare Sareena rather than kill her.
Later in the game, Sareena catches up with Sub-Zero. Having experienced a change of heart, she turns against her former master and helps Sub-Zero defeat Quan Chi. However, before she can escape to Earthrealm with her new ally, she is ambushed by Shinnok, whose attack appears to kill her.
As it turns out, Sareena didn't die. Rather, her human form was destroyed. She suffered, trapped in the Netherealm for years, until she found the portal that Quan Chi and Scorpion had previously used to escape the Netherealm. Once free, she found herself in Outworld and managed to regain both her strength and her human form.
In her canon ending, Sareena eventually came across the younger brother of the original Sub-Zero. The younger Sub-Zero assists Sareena by taking her to Earthrealm, where she is granted sanctuary with the Lin Kuei.
Sareena accompanies Sub-Zero into the Netherealm and saves him from an ambush. Unfortunately, she loses control of her human form soon after and returns to her monstrous, demonic appearance. When Sub-Zero attacks mistakenly attacks her, she flees.
After becoming separated from Sub-Zero, Sareena is captured by Quan Chi, who desires the key she possesses to enter the Lin Kuei temple. When she resists, Quan Chi uses his power to restore Sareena's human form. He then convinces her that as a demon of the Netherealm, she is a being of evil, and successfully tricks her into returning to his service.
Upon defeating Blaze, Sareena is knocked unconscious, but awakens to find Sub-Zero providing her aid. She also learns that she had been granted the same form of freezing power controlled by Sub-Zero. She confronts Quan Chi and uses her new power to freeze him solid. Afterward, Sareena and Sub-Zero take the frozen Quan Chi to the Lin Kuei temple, where he will remain imprisoned forever.