Deus Ex Machina
The god of time and space Yukiterus supposed imaginary friend and the mastermind behind the game. He is looking for a successor which is why he gave future diaries to twelve candidates and placed them in a game of life and death. He seems to favor Yukiteru the most out of all the other candidates as his next possible successor due to the miracles Yukiteru is able to pull off not paying attention to the fact that Yuno is helping him. Deus means God in Latin.