The main events in the Warcraft Lich King story include Arthas' transformation. First, he was a paladin with good intentions. But then he was influenced by the Lich King's power. His journey to Northrend to find the source of the plague was crucial. After becoming the Lich King, his rule over Icecrown and the spreading of the Scourge across Azeroth were major events. His battles against heroes from the Alliance and Horde, which determined the fate of many regions, were also very important in this story.
One main event was Arthas' corruption. He picked up Frostmourne, which led to his downfall. Another is the creation of the Scourge. Arthas used his new - found power to raise the dead and form this terrifying army. Also, his battles against the living in Azeroth, like the attacks on various kingdoms, are significant events.