The true "Master of the Universe" is, of course, God.
(Oxford English Dictionary)
master of the universe
b. A person who is exceptionally successful in business.
Coined by T. Wolfe with explicit reference to the action figures defined at sense 2a.
1987 T. WOLFE Bonfire of Vanities i. 12 He had picked up the telephone and taken an order for zero-coupon bonds that had brought him a $50,000 commission, just like that... On Wall Street he and a few others..had become precisely that. Masters of the Universe. There was..no limit whatsoever!
22 October 1987, New York Times, pg. B1:
Sherman McCoy, who was 38 years old and owned a 14-room Park Avenue apartment and a house on Old Drover's Mooring Lane in Southampton, had taken a telephone order for zero-coupon bonds that brought him a $50,000 commission just like that when the phrase - Masters of the Universe - first bubbled into his brain, then burst.
On Wall Street, Mr. McCoy and "a few others" -- how many? three hundred, four hundred, five hundred? - had become precisely that...Masters of the Universe. There was...no limit whatsoever!