Golbez, real name Theodor, and called Man in Black before his identity is revealed in The After Years, is a non-player character in Final Fantasy IV and a playable character in Final Fantasy IV: The After Years. In Final Fantasy IV, he is an antagonist, a powerful sorcerer who pursues the Crystals. In The After Years, Golbez returns as a playable character.
In Final Fantasy IV, Golbez is a tall imposing man in dark blue and black armor with gold trimmings and a helmet with tall horns. The lining of his cape has been both red and blue sometimes even in the same game—the 3D remake release shows Golbez's official render with a blue lining, but his in-game appearance has a red lining. The exact color of his armor has also varied between appearances, from light blue to dark blue to black.
Through the majority of Final Fantasy IV, Golbez is a cruel and heartless man who will stop at nothing to obtain the Crystals, destroying anyone and anything that stands in his way. He is a cunning manipulator, tricking Cecil and his allies into retrieving two Crystals for him, and otherwise luring them into traps.
As Fusoya later reveals, Golbez is being manipulated by a powerful Lunarian named Zemus by bonding Golbez's thoughts with his. Awakened, Golbez's personality returns to his true self; Golbez is horrified by his actions and feelings of hatred. Golbez's true personality is that of a caring, self-sacrificing, and empathetic individual.