Killer Frost

Killer Frost worked as a member of the Suicide Squad on a mission to assassinate the Riddler.

Assault on Arkham Incident
Killer Frost was initially seen robbing a Gotham City bank, freezing the occupants inside, and engaged the G.C.P.D. in battle after her escape car left her behind before she was apprehended and forced to join the Suicide Squad. Frost eventually woke up in a secured room alongside the other Suicide Squad members with her hands bound together in a metallic mechanism. King Shark briefly attempted to eat her, but was quickly neutralized by her. After being briefed alongside the rest of the Suicide Squad by Amanda Waller, Frost was gassed and woke up locked to a metal chair that was soon after enclosed in a metal crate that was dropped into Gotham City via aircraft.

During the fall, Frost's parachute malfunctioned, she crashed into King Shark, and the two of them landed on top of a parked vehicle that was crushed on impact. Soon after, Frost, along with the rest of the Suicide Squad entered the sewers via a manhole, and she sat atop King Shark's shoulder for the duration of the trek to the Iceberg Lounge. After gearing up there, Frost was contacted on a secure line by Waller and was given the secret task of assassinating the Riddler, unbeknownst to the rest of the team. Frost was snuck into Arkham Asylum through the Arkham Morgue in a body bag naked by a disguised Captain Boomerang.

However, the latter proceeded to knock on her head three times hard enough to give her discomfort in order to sell the act, which resulted in her, after awakening and killing the orderly, proceeding to exact revenge by kneeing him in the groin. During the infiltration of Arkham Asylum, Killer Frost located the Riddler via a computer in the Security Room. Killer Frost decided against killing him when she learned the reason that she was sent to assassinate him - Riddler knew how to disable the nano bombs that were implanted in the members of the Suicide Squad. After the Joker broke free and set all the patients of Arkham loose, Frost tried to escape by stealing a police car, killed an inmate in the process, and froze Two-Face's head. However, Bane, one of the released inmates, grabbed and threw the car that Killer Frost was trying to drive, which caused it to explode, as it is unsure whether she survived the explosion leaving her ultimate fate unknown.

Personality
Killer Frost seemed to have a fearless, non-nonsense personality, as she told King Shark to back off when threatening her and that she'd freeze him if he tried anything; she similarly threatened Riddler when he tried to toy with her with his mind games. She does have a strong sense of self-preservation as she was terrified when Amanda Waller revealed that she had implanted a bomb in her neck and did not hesitate abandon the remaining members of The Suicide Squad after her bomb was deactivated. Surprisingly, she had a sense of humor as she laughed at King Shark's jokes and even made puns herself. In spite of her cold and sarcastic personality, she was capable of some degree of empathy, as she patiently helped to ease Killer Shark's acrophobia and was the only person out of the Squad who was genuinely upset over his death.

Batman: Assault on Arkham
Killer Frost appeared to have blue ice hair, in what seemed to be relaxed curls and had pale white skin with a blue leotard, that in the middle, had a blue diamond with medal around in the the shape of a compass and only went from neck to the beginning of her legs, with long winter gloves that went down to the hands and she had ice blue hands when freezing and high heeled boots with long white-ish parts that went close to the suit.

Quotes

 * "Try it, fish fingers, and I'll show you the meaning of cold-blooded."(King Shark)
 * "Pass."(Amanda Waller)
 * "Yeah, what's in my neck? A tracker?"(Amanda Waller)
 * "That's insane."(Amanda Waller)
 * "Screw that."(Amanda Waller)
 * "Well, I'm convinced."(Harley Quinn)
 * "Ha, ha, ha."(King Shark)
 * "We're not gonna make it!"
 * "Unh. Aah!"
 * "Good one. Good shark."(King Shark)
 * "Wah-Wah."(Harley Quinn)
 * "I'm listening." (to Amanda Waller in her earpiece)
 * "The Joker has a dirty bomb? That gives me the chills."(to Deadshot and Captain Boomerang)
 * "That's payback, you dumbass."(Captain Boomerang)
 * "Walk it off, Captain Kangaroo."(Captain Boomerang)
 * "Where do we even begin?"
 * "Mr. Freeze's gun! Scoooore!"
 * "Ugh!"(tries to lift Mr. Freeze's gun)
 * "Thanks."(King Shark)
 * "It's Batman!"
 * "Nothing gets past you, genius."(Riddler)
 * "I'll make this fast."(Riddler)
 * "The Wall says you screwed her and to make an example out of you."(Riddler)
 * "I don't ask questions."(Riddler)
 * "My only question is why Waller don't just blow your head off with your nanobomb."(Riddler)
 * "Wait, what?"(Riddler)
 * "That worked well."
 * "Wow, I hate you. Unh!"(Riddler)
 * "Somewhat. Glad you made it."(King Shark)
 * "He knows how to turn off the bombs."(to Deadshot about Riddler)
 * "I'll guide you. Trust me."(King Shark)
 * "Step on it!"(King Shark)
 * "Go to the right!"(King Shark)
 * "Do it again!"(Riddler)
 * "Because the bomb in his neck didn't diffuse, you asshole!"(to Captain Boomerang about King Shark)
 * "This place is crawling with cops!"(to Deadshot and Captain Boomerang)
 * "Why the hell are we running?"
 * "Uh, fellas?"(Deadshot and Captain Boomerang)
 * "Guys? Guys? Listen, I-"(Deadshot and Captain Boomerang)
 * "Guys! Batman's here!"(Deadshot and Captain Boomerang)
 * "Yeah, but what'll get us far enough to escape that blast?"(Captain Boomerang)
 * "Out of my way, loser!"(Captain Boomerang)

Trivia

 * Killer Frost could power Mr. Freeze's Freeze Gun with her bare hands.
 * Killer Frost was shown to get along well with King Shark.
 * Killer Frost possessed the power of Thermokinetic Cryokinesis: the ability to generate dangerously low temperatures from her body, freeze people at will, and convert heat into cold. It is also implied that her mastery of her power was such that not even heat/flame-based weaponry such as flamethrowers could affect her.
 * In the original comics, Louise Lincoln was a scientist who willingly transformed herself into a superhuman after the death of her close friend, Crystal Snow, the original Killer Frost. Louise assumed the identity of Killer Frost out of mourning and wrath for her friend's death at the hands of superheroes and became a murderous vigilante as a result. Whether or not this applies to the Arkhamverse version of the character is unknown.
 * In Batman: Arkham Knight, there were stores named Frost Diamonds and Snow's Drug Store. That was likely a reference to Caitlin Snow, who was another incarnation of Killer Frost.