Arthas

From Blizzard's New MMO Wiki

(Warcraft Universe)

Arthas Menethil, Crown Prince of Lordaeron and Knight of the Silver Hand, was the son of King Terenas Menethil II and heir to the throne. He was trained as a paladin by Uther the Lightbringer, and had a romantic relationship with the sorceress Jaina Proudmoore. But despite his promising beginning, Arthas became one of the most powerful and evil beings Azeroth would ever experience when he merged with the Lich King. He is voiced by Justin Gross in Warcraft III: Reign of Chaos and The Frozen Throne, and Patrick Seitz in World of Warcraft: Wrath of the Lich King.