Daniel "Dan" Engler (born November 20, 1977) is an American professional wrestling referee, better known by his former ring name, Rudy Charles, best known for his time as a referee in Total Nonstop Action Wrestling (TNA), where he was the promotion's senior referee. Also has worked in 2011 with SWE, Supreme Wrestling Entertainment, in Wisconsin. In July 2013 Charles joined WWE at their Performance Center as a referee for WWE NXT. He is currently signed to WWE.