Frost

"Killer Frost" is Caitlin Snow's alternative personality. Since a young age, Killer Frost existed within Caitlin Snow. However, due to unknown reasons, Caitlin Snow blocked her out for several years until her time on Team Flash, when Killer Frost reemerged.

Biography
When Caitlin Snow was young, she fell from her bike during an accident, causing Killer Frost to emerge for the first time.

Powers

 * Meta-human physiology: Prior to the Flashpoint event, Caitlin displayed no meta-human potential after being subjected to tests by several different sources. After the events of Flashpoint her powers developed, however, it is implied that her meta-human gene could have simply been dormant before. Caitlin recalled an incident from childhood in which she became Killer Frost, indicating that she was a meta-human prior the particle accelerator explosion.
 * Energy absorption/Cryokinesis: Killer Frost's powers work by absorbing all existing heat around her, thereby reducing the temperature and to freeze targets well-below negative 370 degrees, even shattering beings as powerful as the Black Flash . Furthermore, her powers can reach such low levels that they can completely negate a speedster's healing powers and alternatively neutralize accelerated decomposing. Killer Frost can create various ice structures with ease, even creating large bullet proof shields that can with standing point blank automatic rifle rounds, as well as launching upon manifestation sharp projectiles in rapid succession, creating an icy blade around her arm or as means of transportation, by producing icy waves of such propulsive strength, with one hand behind her, to propel herself forth across an ice slide she forms before her with her other hand, similar to Firestorm's fire-based propulsion ability. Her powers can also affect the weather around her, dropping the climate of the area and cause it to snow. She can also freeze objects without direct contact shown when she froze H.R's coffee from afar. A tell-tale sign of her accessing her powers is producing icy mist from her hands. As displayed by DeVoe, however, it would appear her ability to absorb energy may have been a power that developed as a result of her exposure to dark matter from the particle accelerator.
 * Freezing kiss: Killer Frost is able to freeze people through a kiss, as shown when she went up against Barry but was stopped by Cisco.
 * Freezing breath: Killer Frost is able to create a fog with her breath. Around six months following the defeat of Savitar, Killer Frost, grew powerful enough to orally produce cold mists with enough momentum to knock several people backwards and off their feet.
 * Cold immunity: Killer Frost exhibits a high resistance to frigid temperatures. She is shown to be able to hold the ice constructs she manifests with little trouble. She was also seen unaffected by a snowstorm she created after escaping S.T.A.R. Labs.
 * Accelerated healing factor: As Killer Frost, she can endure more grievous injuries and likewise heal much faster than even a speedster, though foreign matter must first be taken out to not impede the healing. After clinically dying from a combination of a seizure and her reopened impalement wound, she was immediately resuscitated into a stable and cognitive state while her wound seamlessly healed completely in seconds. However, her healing powers only work when her Killer Frost side takes over, as wounds inflicted by Amunet left bruising and required stitches. Interestingly enough, Caitlin's Earth Two doppleganger seemed to lack this aspect of their near-similar meta-human powers, which was what led to Earth Two Killer Frost's death at Zoom's hand.