While most people never really caught his last name, Prince Arthas, as he was affectionately known in Warcraft 3, was the Crown Prince of Azeroth, successor to the throne of his father, King Terenas Menethil. While training in the arts of fighting in his youth, he found time to play around with childhood friend Jaina Proudmoore.

Arthas was quick to join the Paladin's order of the Silver Hand where he meets legendary Paladin and mentor Uther Lightbringer. When dispatched by King Terenas to quell the disturbances occurring in the Orc internment camps to the north of Lordaeron, Arthas and Uther defeated the remaining Orc clans.

But soon they heard of more disturbing news about a plague of undeath sweeping across the outlying villages near Lordaeron. Arthas, reunited with brilliant sorceress Jaina, set forth toward Brill and Stratholme to track down the source of the plague.

It wasn't very obvious: it was an infected grain shipment that spread undeath throughout the outskirts of northern Lordaeron, successfully accomplished by evil wizard Kel'Thuzad while masterminded by the Lich King, Ner'Zhul.

Because Arthas and Jaina were totally sidetracked from their mission (they killed Kel'Thuzad yet haven't stopped the spread of the plague), Arthas decides to head over to Stratholme with Jaina and Uther to halt the shipment and distribution of the tainted grain. They fail terribly and Arthas decided he would rather cut down his own people than have their souls stolen by the Demon Lord Mal'Ganis.

Despite Jaina and Uther's refusal of the Prince's orders, Arthas continued the slaughter of the city, yet was never able to strike Mal'Ganis down. He follows the demon up to the cold, isolated Northrend. After a brief meeting with old friend Muradin Bronzebeard, he discovered the myth about the mystical runeblade, Frostmourne.

He traded Muradin's life to be the keeper of the soul-stealing, refrigerated sword, and soon defeated Mal'Ganis and banishes his forces from the North. Arthas returns triumphant to his father, only to slay him and collapse the great kingdom Lordaeron used to be.

WoW Insider has a much more extended look into Arthas' life, and you can hop over to it from the "Read" link below. Arthas has yet to make an appearance in World of Warcraft.