The mysterious character is an unnamed character in Contra: Hard Corps. He is an odd-looking man who is always searching for potential participants who would like to try their luck in the battle arena.
A rather odd-looking individual wearing a suit, top hat, red bow tie, and sunglasses. He will ask the player if they want to try their luck in the battle arena for a chance to win big money. If the player agrees, they will enter a crowded fighting arena where they will fight Simondo Belmont, Psycho Mother, and Warp Bomber. If they succeed in defeating all three, a secret ending will take place where the heroes are sucked into an inter-dimensional portal and are sent back in time to a prehistoric age, where and become leaders of a tribe of apes.
If the player did not accept the mysterious character's deal, they will simply return back to the room below.