Arthas Menethil was a human Paladin who turned into a Death Knight and then merged with the Lich King. Arthas was one of the primary protagonists and antagonists of the Warcraft universe. Arthas has slaughtered and destroyed many civilizations as a Death Knight. As a human he hated evil and those who corrupted the innocent. Ironic that he would become the thing he was fighting all along.
He was originally voiced by Justin Gross for Warcraft III: Reign of Chaos and the expansion pack for Warcraft III: The Frozen Throne. Gross declined to reprise his role for the Wrath of the Lich King when Blizzard Entertainment supposedly offered him an embarrassingly low amount of money. With Gross not returning Blizzard hired a new voice actor, and Arthas was then voiced by Patrick Seitz for Wrath of the Lich King.