What fictional universe is aired on the CW for The Flash?
Arrowverse The Arrowverse is a shared fictional universe that is centered on television series airing on The CW, developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, Phil Klemmer, and Geoff Johns, based on characters appearing in publications by DC Comics. The shared universe, much like the DC Universe in comic books or the cinematic DC Extended Universe, was established by crossing over common plot elements, settings, cast, and characters. The Arrowverse stars Stephen Amell as Oliver Queen / Green Arrow, Grant Gustin as Barry Allen / Flash, Megalyn Echikunwoke as Mari Jiwe McCabe / Vixen, with an ensemble cast leading "Legends of Tomorrow", including Arthur Darvill as Rip Hunter, Caity Lotz as Sara Lance / White Canary, Brandon Routh as Ray Palmer / Atom, Dominic Purcell as Mick Rory / Heat Wave, with Victor Garber and Franz Drameh as Martin Stein & Jefferson "Jax" Jackson / Firestorm. Russell Tovey stars as Ray Terrill / The Ray.
Legends of Tomorrow DC's Legends of Tomorrow, or simply Legends of Tomorrow, is an American superhero action-adventure television series developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, and Phil Klemmer, who are also executive producers along with Sarah Schechter and Chris Fedak; Klemmer and Fedak serve as showrunners. The series, based on the characters of DC Comics, airs on The CW and is a spin-off from "Arrow" and "The Flash", existing in the same fictional universe. The series premiered on January 21, 2016. In January 2017, The CW renewed the series for a third season, which is scheduled to debut on October 10, 2017.