Which company, headed by Thomas Tull, produced the 2013 film that was the first installment in the DC Extended Universe?
Thomas Tull: Thomas Tull (born 1970) is an American businessman and film producer. Thomas Tull:  He is the former chairman of the Board and chief executive officer (CEO) of Legendary Entertainment. Thomas Tull:  His firm has produced and/or financed several major motion pictures, including "The Dark Knight Trilogy", "The Hangover" and its sequels, "300", "Man of Steel" and others. Man of Steel (film):  It is the first installment in the DC Extended Universe (DCEU).
Legendary Entertainment