Killer Frost is a character and an anti-heroine from DC Comics
Caitlin Snow was a young and bright scientist working for S.T.A.R. Labs assigned to an underfunded S.T.A.R. Labs Outpost #72 in the Arctic Circle, where the deceased researcher Dr. Louise Lincoln had been working on a Self-Sustaining Thermodynamic Ultraconductor Engine that could subvert the second law of thermodynamics in order to create perpetual motion. Caitlin became interested in continuing Lincoln's work, in spite of her colleagues warning her against it.
When Caitlin succeeded in finishing the S.T.U. engine, her colleagues turned on her and revealing themselves to be working for H.I.V.E., as they were expected to ensure that the engine was never made public in order to protect H.I.V.E.'s investments in the energy industry. Furthermore, they were also responsible for Lincoln's death, and they then proceeded in silencing Caitlin by placing her in the working S.T.U. engine. In a panic, Caitlin ripped out the wires for the engine's coolant system, consequently infusing her biological makeup with ice. As a result, she became a vampiric being who craved for heat, and killed the H.I.V.E. agents.
After carrying out her vengeance, Caitlin continued to search for other sources of heat; she attacked a Norwegian research camp and stole their helicopter to fly to her hometown of Pittsburgh, where she encountered and fought Firestorm. While fighting Firestorm, Caitlin discovered that Firestorm's powers can temporarily heal her condition, and devoted her time to seeking and confronting him. She soon learned about the Firestorm Matrix and attempted to recreate it.
Killer Frost was captured at some point after, and transported to Belle Reve where she was forced to join the Suicide Squad. After reforming and saving the world from Eclipso, Batman had her released on parole from Belle Reve and she joined the new Justice League of America.