Warcraft III: The Frozen Throne

Although the armies of humans, orcs, as well as their allies recovered from their war up against the  mighty Burning Legion, Arthas Menethil , now a Death Knight, killed a majority of the living inhabitants of Azeroth's Eastern Kingdoms in honor of the Scourge. But new forces surfaced that were ready to confront and eliminate Arthas and his band of undead scourge minions: the banshee Sylvanas Windrunner rebelled, making a sub faction of undead referred to as the Forsaken, and also the demonic night elf known as Illidan Stormrage dispatched his military towards the wintry continent of Northrend to launch an assault at the Lich King. Arthas raced to his protect his master and conquered Illidan, who left to Outland in a sense of shame. At long last near to the throne of the Scourge's power, Arthas willingly performed the unimaginable, and voluntarily combined his very own soul with his masters the Lich King.