On August 21, 2008, Blizzard unveiled the opening cinematic for Wrath of the Lich King, the upcoming expansion to World of Warcraft. It was first presented at the Leipzig Games Conference in Germany and was later made available for download from the World of Warcraft official website.1up.com: GC 2008: Blizzard Releases Wrath of the Lich King Opening Cinematic (August 21, 2008)

The video opens with a shot of the lich king, Arthas, quietly sitting atop a throne of ice as the voice of his dead father speaks promisingly of his future. He is then shown wandering through a vast field of snow, stopping halfway towards the edge of a mountain cliff before suddenly plunging his Frostmourne blade into the ground. An enormous skeletal dragon erupts from beneath the surface and dives over the cliff into the valley below, revealing a vast army of undead. As the Frost Wyrm passes over the soldiers, they turn towards Arthas and let out a violent roar as their eyes take on an eerie blue glow.

The original Lich King was the orc shaman Ner'zhul, whose soul was trapped within a magical frozen throne by Kil'jaeden the Deceiver. Ner'zhul eventually transformed into the Lich King, a being of great power who was sent to the land of Azeroth. There, he unleashed the Scourge, a plague that transformed the people into an undead army for the Burning Legion.

A human army, led by Uther Lightbringer and accompanied by Lordaeron's Prince Arthas Menethil, set out to battle the undead army and find the source of the Scourge. Arthas became increasingly discouraged as he saw fallen comrades rise again to join the undiminishing undead army. He ordered the pre-emptive destruction of the city of Stratholme in an attempt to halt the Scourge. He took up the soul-devouring sword, Frostmourne, believing that it would help save his people.

Arthas' actions made him susceptible to the Lich King's siren call. Ner'zhul transformed Arthas into the first Death Knight, who proceeded to assassinate his own father and unleash a deluge of destruction on his homeland. Arthas then used Frostmourne to shatter the Frozen Throne. He donned the armor of Ner'zhul and the two souls merged to form a Lich King of seemingly unstoppable power.Official Site: Rise of the Lich King WoW Insider: Know Your Lore: Arthas (February 23, 2007)