Fiyero is a character in the non-canonical Wicked: The Life and Times of the Wicked Witch of the West.
He is a Vinkuus student at Shiz University. He's betrothed to another winkie, Sarima, whom he later marries and has three kids with. He is described as a dark-skinned man with diamond-shaped tattoos in the novel, but isn't portrayed that way in the musical (probably because it would be hard to show on stage.)
Norbert Leo Butz played Fiyero in the Orignal Broadway Cast of Wicked.