Barry Allen: The Silver Age Flash. He is a brilliant scientist whose tragedy—his mother's unsolved murder—drives his dedication to justice and creates the foundational mythos of the character.

Caitlin Snow (Killer Frost): A top-tier bioengineering and medical expert who operates as the team's medic and scientist. Tragic exposure to cryokinetic powers results in her developing a dual-persona as the icy, heroic, but occasionally conflicted Killer Frost.

Iris West: Barry’s anchor and great love. She is an intrepid investigative reporter for Central City who provides an emotional compass and narrative grounding for the various speedsters in her family.

A brilliant, warm-hearted Central City detective who becomes Barry's adoptive father and father-in-law. He is the law enforcement pillar of Barry's inner circle.

S.T.A.R. Labs’ brilliant mechanical engineering genius and Barry's best friend. In comic lore, he develops metahuman powers that allow him to manipulate sonic waves and open dimensional rifts.

The enigmatic, wheelchair-bound visionary behind S.T.A.R. Labs who serves as Barry's mentor

Barry’s wrongfully imprisoned father, serving a life sentence for the murder of Barry's mother , Nora Allen.

General Zod's son is who is the incarnation of the unstoppable monster Doomsday. He was not born naturally; rather, Zod and his wife Faora artificially engineered him by combining their DNA with that of the most violent creatures on Krypton before he came to Earth[Central City]

The Reverse Flash Barry’s ultimate nemesis from the future. A twisted fanatic, he possesses the Negative Speed Force and is responsible for murdering Barry’s mother. Thawne represents everything the Flash stands against, using his speed for manipulation and destruction.

Ronnie Raymond is a S.T.A.R. Labs structural engineer and Caitlin Snow's fiancé. He survives the particle accelerator explosion which happened a year ago but bonds with physicist Martin Stein to become the metahuman hero, Firestorm