Frost (Earth-1: Pre-Crisis)

"I used to be afraid that because we shared a body, I was only gonna get to live half a life, that I was only gonna be half a person. I realize now, that isn't true. You didn't take anything from me. In fact, it's just the opposite. You make my life complete. I gotta be honest, I'm a little worried that we're not gonna make it out of this and that I might lose you forever. And I can't handle that. I would die. I love you more than anything."

- Frost to Caitlin Snow

Frost, formerly known as Killer Frost, was the former alter of Caitlin Snow when Snow was cured of amyotrophic lateral sclerosis (ALS) and developed dissociative identity disorder.

Frost originally worked in the criminal world alongside Savitar, and later served under Amunet Black. Frost soon reformed and joined Team Flash and switched positions with Snow regularly. Eventually, the injury caused by Eva McCulloch's Mirror Gauntlet split Frost and Snow apart.

Originally thinking she could live a normal life, Frost was hunted by government official Kristen Kramer and sent to prison for his crimes before rebranding as a vigilante. Luckily, Frost's heroic actions during a prison break allowed her to be on parole, rejoining Team Flash's actions.

Early Life
At some point of Caitlin Snow's life, Frost was created and became a split personality of her. However, she was hidden until recent years. In 2019, Snow 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 Doctor 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 Snow unconscious. A 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, Snow suggested seeing 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 knocks the team unconscious.

Invasion of Central City
Waking up from her injuries, Snow sees Barry crying over Iris and assisted in bringing 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 in 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 agreed to a road trip.

Split from Snow
A week after the Invasion, Frost and Snow 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 attempting to fix the Quantum Splicer for the merge. Frost then sabotaged the device and was confronted by Snow, with Frost telling her that she didn't want to merge after finally getting to live a life with her own 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 Snow looked for her. After telling her about her own fears, Snow offered Frost to sleep in an extra room in her apartment and considered her a sister.

Life in Prison
"Taking away a metahuman's powers isn't the same thing as taking away a gun from a criminal. Erasing our powers is erasing our identity. It's saying, "Hey, you were made bad, change that." But shouldn't justice be about changing the way a person acts, not the way they were born? I get it. You fear us because we're different. You'd feel safer if we were the same. But different can't be cured. It's here to stay. We're here to stay. Some of you only think of me as the criminal I used to be. Back then, I was only interested in protecting myself. But then, I found someone else worth protecting. And protecting that person led me to protecting a whole city. And slowly I changed. I learned how... I learned how to be selfless instead of selfish. I learned that I'm my best self when I'm protecting other people."

- Frost

Powers

 * Cryogenic Physiology: In an attempt to cure Caitlin Snow's amyotrophic lateral sclerosis (ALS), Thomas Snow experimented on both himself and his daughter, creating an artificial Split Personality for both of them and a cryogenic physiology when the alter fronts. However, Frost was later split from the body of Caitlin Snow when the effects of Eva McCulloch's Mirror Gauntlet spliced their bodies.
 * Thermokinetic Cryokinesis: By drawing heat, Frost was able to freeze objects within a radius without even touching them.
 * Accelerated Healing: Also known as "ice healing", Frost could use her cryokinesis to speed up the healing process.
 * Cryokinetic Breath: Frost was capable of breathing out cold air and freezing objects.
 * Cryokinetic Blasts: Frost had the ability to create cold blasts of ice from her bare hands.
 * Cryokinetic Constructs: With precise concentration, Frost could create objects with ice and use them as weapons, most commonly daggers for hand-to-hand combat.
 * Superhuman Durability: Despite being hit with a bullet, Frost only suffered from minor injuries.
 * "Grief Energy" Mutations: Frost voluntarily absorbed grief energy from Deathstorm's home dimension, greatly enhancing her abilities and making herself powerful enough to combat Deathstorm.
 * "Grief Energy" Absorption: Hellfrost had the ability to absorb the apparitions sent by Deathstorm by consuming the grief energy required to create them.
 * Pyrokinesis: As Hellfrost, Frost was able to generate and shoot flames based on cold fusion.
 * Flight: By combining her cryokinetic constructs and her flames, Hellfrost could lift herself above the ground and defy gravity.

Former Powers

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

Abilities

 * Chemistry: On the "passenger seat" for years in Snow's mind, Frost learned chemistry from the former's early years in school.
 * Medical Knowledge: Like learning chemistry from Snow, Frost was able to have the same knowledge of medication and acts as a doctor in the field as well as in S.T.A.R. Labs.
 * Hand-to-Hand Combat: Frost fought several Reflections using hand-to-hand combat.
 * Peak of Physical Condition: Frost was in excellent shape after training herself in the S.T.A.R. Labs gym.

Weaknesses

 * Power-Dampening Technology: Frost's powers were dampened when wearing government-issued cuffs.
 * Metahuman Cure: Due to Frost's unique process of developing powers, Team Flash was uncertain that the Metahuman cure will or will not be harmful to Frost. Later, Carla Tannhauser ran several tests and revealed that it would remove her powers without killing her.
 * Cold Fusion Flames: While Frost did not sweat, the "Black Flame" was able to make her do so and burn her skin.

Former Equipment

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