|First appearance||Underworld: Evolution|
|Created by|| Kevin Grevioux|
Len Wiseman &
|Family|| Alexander Corvinus (father, deceased)|
Helena Corvinus (mother, deceased)
Markus Corvinus (identical twin brother, deceased)
unnamed Corvinus (brother, deceased)
Michael Corvin (distant grandnephew)
William Corvinus (in hungarian: Corvin Vilmos) is the first Werewolf Elder in the Underworld universe. He is the son of the first immortal and was bitten by a wolf, thus turning him into a werewolf. He is played by Brian Steele.
William was the son of Alexander Corvinus and the twin brother of Markus Corvinus. Both were born sometime in the 5th century. He, along with Markus, inherited the genetic immortality strain from his father. This strain was created once the unique Corvinus blood type came into contact with a regional plague. Corvinus' DNA somehow changed the plague, making it beneficial and conferring immortality. Markus was eventually bitten by a bat and William by a wolf. The introduction of the new animal DNA caused each sibling to further mutate, thus William became the first true Werewolf. He has long silver fur and a wolf head. Unlike later werewolves known as Lycans, he could not revert back to human form. His lycanthropy virus was much more infectious than Markus' vampire virus, even allowing dead victims to transform.
In 1202, he was captured by Viktor's Death Dealers just after he infected an entire village. Against Markus' wishes, William was imprisoned by Viktor, far from Markus' reach. This caused Markus to swear vengeance against Viktor and those loyal to him.
Centuries later, William was freed from his dungeon by Markus. Markus and William both shared a bond that Alexander never truly saw. It was this remaining bond that caused William to recognize Markus, even through his own bestial nature. William proved to be a powerful creature, despite his centuries of confinement with no food to feed on. He infected the Cleaners who came to fight him and also combated the hybrid Michael Corvin, descendant of his mortal brother, absorbing immense amounts of damage with no obvious signs of trauma done to him. He was unable to defeat Michael, who tore apart the Lycan Elder's head with his bare hands.