Following The Clone Wars series’ cancellation, Rex returned in Star Wars Rebels with fellow clones Wolffe and Gregor.
Captain Rex (officially designated CT-7567) was introduced in the 2008 Star Wars: The Clone Wars animated movie, and would go on to be one of the principal characters in the Clone Wars TV series.
Because clones age twice as fast as humans, Rex and the others now looked middle-aged when they were actually only a couple decades old.
Rex was most often seen fighting alongside Anakin Skywalker and Ahsoka Tano, but like the other clones in the series, he was voiced by Dee Bradley Baker.