Toonami is an action-animation block that aired on Cartoon Network from 1997 to 2008, and as of 2012 is now currently airing on [adult swim]. Starting off on weekday afternoons and then eventually being moved to Saturday nights, it is known for popularizing Japanese anime in the states, being responsible for premiering and introducing anime shows such as Sailor Moon, Dragon Ball Z , Robotech, Outlaw Star , Tenchi Muyo! , Gundam Wing , The Big O , Naruto , and One Piece to western audiences, as well as airing western shows such as Jonny Quest: The Real Adventures, ReBoot, ThunderCats , Batman , SupermanHe-Man and the Masters of the UniverseJustice League , and Megas XLR . Toonami was also known for having a darker atmosphere than other animation blocks, as well as its ambient music, and well-edited promos that were narrated by Peter Cullen (who is famously known as the voice of Optimus Prime in The Transformers).

In 2008, Toonami was shut down due to low ratings, with the shows airing at the time being aired during regular Cartoon Network hours before being removed as well. On April 1st 2012, [adult swim] began their annual April Fools Day act of airing The Room, only to then cut to a brief return of the TOM 3 iteration of Toonami. The rest of the night continued with the usual airing of Bleach, followed by episodes of classic Toonami shows, advertisements for said shows' DVD releases, and a game review of Mass Effect 3. The act garnered enough positive attention that Toonami was eventually revived as a Saturday night action-animation block, airing on [adult swim] hours and replacing [adult swim] Action.

Voltron: Defender of the Universe aired from March 17, 1997 to May 29, 1997 as part of their action block Toonami, with the remaining 72 episodes of Voltron: Defender of the Universe series that had not been aired on Toonami, and went on to show reruns of previous episodes. Reruns of Voltron: Defender of the Universe continued to air from May 30, 1997 until February 27, 2000, after which it was removed from the programming schedule.

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