Frost's History
Original Timeline
After Sub-Zero became the Grand Master of the Lin Kuei clan, he organized a tournament to recruit powerful warriors. The winner was Frost, showing exceptional skills; Frost then becomes the apprentice of Sub-Zero. After a time of hard and arduous training, Frost increases her combat ability, while her arrogance also increased.
During the events of Mortal Kombat: Deadly Alliance, when Raiden asked Sub-Zero for help to end the Mortal Alliance, she went with Sub-Zero to the Outside World. After this, she froze Sub-Zero, leaving him motionless for a few seconds so she could steal the Dragon Medallion that he carried on his chest. Without possessing the strength and discipline necessary to control the power of the medallion, her own freezing power ended up burying her in an ice coffin. Sub-Zero felt very sorry for her because she had taken a lot of appreciation and affection, but he knew that he should give her a dignified burial, so he took her to some ancient ruins where he discovered that they both were descendants of the criomantes, a warrior culture able to master the ice.
He also found an armor of his ancestors and chose to leave it there. Some time later, Sub-Zero returns to the Lin Kuei temple, only to find that Frost has returned, accidentally resurrected by Taven, in his search for his mother's gift. Frost could only remember Sub-Zero, and she murdered all of the Lin Kuei that she found in his path. Believing that Taven was Sub-Zero, Frost fought him. The last blow Taven did to Frost, allowed her to regain his sanity. However, Frost is arrested again by Sub-Zero, who freezes and contains her in the temple until she regains her sanity.
Current Timeline
Frost appears in the Mortal Kombat X prequel comic, as a fighter in a fight club with death fights, holding a record of 21 fights won, undefeated, with 19 perfect victories and having killed all her opponents. When she has to face Cassie Cage, at first Frost takes the lead by brutally beating Cassie, but she reacts using unpredictable movements inherited from her father, leaving Frost unconscious. The stadium manager forces Cassie to kill Frost, but at that time two members of the Black Dragon clan, Jarek and Tasia, break in. Cassie and Jacqui Briggs, who had accompanied her to the place, rescue Frost and flee. Both notice the heaviness and low temperature of Frost without realizing that she was a cryomant, since Frost had not exhibited her powers to both. Frost is removed on a stretcher by paramedics.
In Mortal Kombat X, Frost appears in the Lin Kuei temple along with Sub-Zero, who helps the Special Forces in their training, at the request of Johnny Cage. Frost is impatient and arrogant, refuses to help the Special Forces and hates that Sub-Zero helps them. She later attempts to kill Scorpion when Sub-Zero invites him to the Lin Kuei temple, leading the already suspicious Scorpion to believe that Sub-Zero plotted to kill him until Sub-Zero froze Frost when she attempted to kill Scorpion from behind.
Later on, during the events of Mortal Kombat 11, on a Sub-Zero and Scorpion mission at the Cyber Lin Kuei factory, guarded by Sektor to manufacture cyborgs in Kronika's service, Frost appears surprisingly, revealing that she has become a cyborg, metallic body but retaining its face and hair. Frost is defeated by Sub-Zero and Scorpion, and left at the factory, unconscious. She then reappears in Kharon's ship, which transports the Earth Warriors to the fortress of Kronika's time to face her and her armies. Frost tackles the ship along with an army of cyber ninjas, but is defeated by Raiden, who is forced to burn her circuits and kill her so that the army of cyber ninjas will shut down, since they were all connected to Frost through a network.