Kyle Nimbus

"'Take your last breath!'"

Kyle Nimbus, nicknamed The Mist by Cisco Ramon, was an assassin from the Darbinyan crime family. He was affected by the S.T.A.R. Labs particle accelerator the night he was supposed to be executed via gas chamber. He later became the first inmate of the makeshift particle accelerator prison under S.T.A.R. Labs. However, he, along with the rest of the imprisoned meta-humans, were eventually freed by Leonard Snart and Lisa Snart.

History
Kyle Nimbus worked as a hit-man for the Darbinyan crime family, until they testified against him in court, and he was arrested by Joe West and sentenced to death by Judge Theresa Howard. On the night he was to be executed, the S.T.A.R. Labs particle accelerator explosion hit the gas chamber he was in, fusing his molecular structure with the toxic gas, hydrogen cyanide. Thought dead, he escaped from the morgue of Iron Heights Prison.

Kyle began his rampage of revenge with the Darbinyans, slaughtering all of them at a family meeting with his poisonous gas, due to their involvement in his execution. Following this, his next target was Judge Howard, who had convicted him, whom he killed in an elevator at the mall, while she was shopping for her daughter's prom dress. The final target of his revenge spree was Detective West, who had arrested him, who ironically enough was visiting Iron Heights at the time. After beginning to kill West, he escaped from the prison with The Flash in pursuit, whom was able to suffocate him by using his super speed to keep him in gas form, thereby depriving him of oxygen, until he fell unconscious. Once he awoke he discovered that he was a prisoner of the particle accelerator-turned-makeshift meta-human prison under S.T.A.R. Labs and furiously tried to get out.

When Harrison Wells was extracting the deceased Farooq Gibran's blood, Nimbus was still attempting to escape from his cell before he saw Wells. Wells smiled and put his finger to his lips, signaling the Mist to keep quiet.

Powers

 * Gas mimicry: Kyle is able to transform himself in to a toxic cloud of hydrogen cyanide mixed with a sedative.

Weaknesses

 * Speed Vacuum: When Barry was fighting Nimbus at the Ferris Air Testing Facility, he created vacuums from his arms making Nimbus draining his gas particles and needing them to recharge.

Trivia

 * Nimbus is the Latin for "aura", as in the cloud type cumulonimbus, a warning sign for thunderstorms.
 * Anthony Carrigan also plays Zsasz in the tv series "Gotham", and he is a hitman for a crime family in both shows.
 * In the DC comics, the Mist is a man whose real name was unknown, who had similar abilities but with a completely different backstory.
 * The character's other aliases included Nimbus.
 * The character had a son named Kyle and then a grandson sharing the same name.
 * The character, however, was not a foe of the Flash, but the archenemy of another superhero, Starman (Ted Knight.)