Frost (Earth-1: Pre-Crisis)

"You know, to be honest, I always kind of felt like a third wheel."

- Frost on her relationship with the Snow Pack

Frost, formerly known as Killer Frost, is the split personality of Caitlin Snow. She is also a reformed criminal and became a vigilante after rebranding her name.

Early life
At some point of Caitlin's life, Frost was created and became a split personality of her. However, she was hidden until recent years. In 2019, Caitlin let Frost to take main control.

In 2017, Frost committed several crimes before reforming. This includes an aggravated assault on Acolyte, an attempted murder on Tracy Brand, two kidnappings of Julian Albert and Cecile Horton.

At some point, Frost read some of Rebecca Silver's books and was aware that Mick Rory is Rebecca.

Black Hole
After the crisis, Frost was sent to fight Dr. Light and was injured by the Photon Rifle blast. Later, Frost tried to use cold healing to help the wound but was unable and caused both herself and Caitlin unconscious. Few hours later, Cisco and Ralph brought a polar bear to visit her at her apartment. As they saw her sick, they made her awake again. Since they were unable to completely heal her, Caitlin suggested to see her mother. However, Frost was unwilling to as she was afraid Carla would hate her. With Ralph's encouragement, she decided to visit Carla.

Return
Four weeks later, Frost returned fully recovered and fought Eva McCulloch. However, due to Barry's depleting emotions, she was not rescued by him and fell unconscious after being shot by Eva's laser cannon. Brought back to S.T.A.R. Labs, Barry was able to synthesize a cure and bring Frost back awake.

Later, Frost fought a "rogue" Barry using Velocity X and powering herself with superhuman speed. However, she was quickly defeated and was brought back to S.T.A.R. Labs by Allegra after the latter's successful defeat of Barry. Despite their effort, the Quantum Ball thrown by Barry before the fight returns and knocked the team unconscious.

Invasion of Central City
Waking up from her injuries, Caitlin sees Barry crying over Iris and assisted to bring her to the med lab. Frost then prepared for the final showdown between Team Flash and Eva's army. However, Cisco's gadgets failed and fled to her. The two then chose to fight the army hand-to-hand.

After Eva realized what she had done, Iris and Barry assisted her on restoring the normalcy and Frost returned to S.T.A.R. Labs. She then bid farewell to Ralph after his extreme injury and told him that she agrees for a road trip.

Split from Caitlin
A week after the Invasion, Frost and Caitlin suffered from headaches and went for a sleep, only to wake up in separate bodies. They then approached Cisco Ramon and surprised him with their sudden change. Cisco later brought them to the Cortex and surprised Barry and Iris.

They then went to the lounge and discussed the prior events to the split. Barry then sped off to fight Psych and later Frost assisted the treatment of his injury. Frost then approached Cisco who was attempted to fix the Quantum Splicer for the merge. Frost then sabotaged the device and was confronted by Caitlin, with Frost telling her that she does not want to merge due to her finally living a life without in her body.

Hours later, Barry, Frost and Cisco went to the Cleary Capital Investments Office and fought Psych. Frost was then quickly placed in a "nightmare" where she was arrested by the CCPD due to her criminal activities in 2017. In the "nightmare", Frost asked Joe who turned her in and suspected Mark, with Joe telling her it was Caitlin Snow.

The trio then returned to S.T.A.R. Labs and suffered from panic attack symptoms. Frost was alone in the Speed Lab fixing the splicer until Caitlin looked for her. After telling her about her own fears, Caitlin offered Frost to sleep in an extra room in her apartment and considered her a sister.

Powers

 * Cryogenic Physiology: Frost was created in an attempt on creating an ALS cure by Caitlin's father.
 * Thermokinesis Cryokinesis: By drawing heat, Frost is able to freeze objects.
 * Superhuman Durability: Despite being hit with a bullet, Frost only suffers from minor injuries.
 * Accelerated Healing: Also known as "ice healing", Frost uses her cryokinesis to speed up the healing process.
 * Ice Breath: Frost is able to breathe out cold air and freeze objects.
 * Mental Connection: As a split personality of Caitlin Snow, the both are able to talk to each other mentally.

Former Powers

 * Powers via Velocity X: Frost injected herself with Velocity X as a countermeasure against The Flash.
 * Superhuman Speed: After injecting herself with Velocity X, Frost gains superhuman speed.
 * Superhuman Durability: Frost is able to survive a fall from a tall skyscraper in high velocity with little injuries.
 * Superhuman Stamina: Despite running long distances, Frost is able to continue moving until the Velocity X wears off.

Abilities

 * Expert Chemist: On the "passenger seat" for years in Caitlin's mind, Frost learned chemistry from Caitlin's early years in school.
 * Expert Medic: Like learning chemistry from Caitlin, Frost is able to have the same knowledge on medication and acts as a doctor on the field as well as in S.T.A.R. Labs.
 * Skilled Hand-to-Hand Combatant: Frost is able to fight several Reflections using hand-to-hand combat.
 * Peak of Physical Condition: Frost is in excellent shape after training herself in the S.T.A.R. Labs gym.

Equipment

 * Frost Suit: Frost wears a navy leather suit with a snowflake emblem on the chest as well as a blue jacket.