DC Comics, Inc. is an American comic book publisher. It is the publishing unit of DC Entertainment, a subsidiary of Warner Bros. DC Comics is one of the largest and oldest American comic book companies and produces material featuring numerous culturally iconic heroic characters including Superman, Batman, The Flash, Wonder Woman, Green Arrow, Nightwing, Green Lantern, and Aquaman. Most of their material takes place in the fictional DC Universe, which also features teams such as the Justice League, the Justice Society of America, the Suicide Squad, and the Teen Titans, and well-known villains such as The Joker, Lex Luthor, Catwoman, Darkseid, Sinestro, Brainiac, Black Adam, Ra's al Ghul and Deathstroke. The company has also published non-DC Universe-related material, including Watchmen, V for Vendetta, and many titles under their alternative imprint Vertigo.