After Sub-Zero became Grandmaster of the Lin Kuei clan, he held a tournament in order to recruit strong warriors. The victor was Frost, whose exceptional skills impressed Sub-Zero. Breaking Lin Kuei tradition, Sub-Zero took her as his protege and trained her personally. With his assistance, her ability to focus her freezing power increased. However, as her skills grew, so did her arrogance. Sub-Zero was unable to teach her humanity.
When Raiden requested Sub-Zero's assistance in defeating the Deadly Alliance, Frost's training was cut short. Sub-Zero brought her with him for assistance, hoping at the same time she would attain perspective and enlightenment through the experience of actual battle. After meeting with the Earthrealm warriors, (one of which was Sonya Blade, who did not get along with Frost), she accompanied Sub-Zero into Outworld.
Once there her intentions for joining the Lin Kuei became apparent. Desiring to become Grandmaster of the clan herself, she immobilized Sub-Zero with a freezing blast, and tore the Dragon Medallion from his chest. Without the strength and discipline required to control the medallion's power, she consumed by her own freezing ability, seemingly killing her.
Forgiving her for her betrayal, Sub-Zero searched for a suitable place to bury her remains. He discovered the ancient ruins of a holy structure erected by the long-lost race of Cryomancers. Sub-Zero became to believe that both Frost and himself were descendants, and laid her body to rest in a sarcophagus before leaving.
However, during the events of Mortal Kombat: Deception, Frost awoke sometime after Sub-Zero's departure, miraculously alive after all. Realizing that she was still in Outworld and that Sub-Zero left her for dead, she swore to make him pay. Frost then returned to the Lin Kuei temple, hearing Sub-Zero was still in Outworld and hoping to kill him. Later, she entered a state of delirium, seeing Sub-Zero everywhere. Frost dispatched many Lin Kuei while in this state until Sub-Zero returned. He deep froze Frost into an ice coffin and placed her in the chamber of the fallen Lin Kuei, sealing it later with an ice wall. Later, as the events of Mortal Kombat: Armageddon begin, Taven revived her from her ice coffin. Frost, still seeing Sub-Zero everywhere, attacked him, but was still defeated by Taven. After the fight, she realized Taven was not Sub-Zero, and left the chamber to parts unknown.
In Frost's Armageddon ending, her strength increased, Frost once again took the Dragon Medallion from Sub-Zero and enhanced her freezing power far beyond her former mentor's. Traveling to Outworld, she located the tomb of her ancestors, the Cryomancers, and planted their souls in the bodies of the current Lin Kuei. Her army of Cryomancers conquered the realms, leaving each of them a frozen wasteland.