Every World of Warcraft player is surely familiar with the character of King Fox Arthas. He is considered one of the greatest villains of Azeroth, but he is also one of the most popular characters among players. However, I think that not everyone knows exactly who the Lich King really is. He wasn't Arthas, or at least not really. The would-be king of Lordaeron was simply a vessel that the Lich King filled with his soul...
The two faces of Prince Arthas
To find out the whole truth about him, we have to go back to the Second War.
When the Horde was defeated, the Legion's plans to conquer Azeroth were in ruins. The demons suffered defeat, but they did not give up. On the contrary, Kil'jaeden learned from it. The Horde lost through internal conflicts and lack of loyalty. The Dark Demon would never allow such a situation to occur again. Another plan has already been born in his mind!
A plan to raise a new, powerful army to conquer Azeroth. All he needed was a strong soul, familiar with the secrets of magic, to keep this army in check. Kil'jaeden knew someone like that. That someone was responsible for the recent shattering of Draenor. Ner'zhul and his subjects, after that catastrophe, had managed to escape into the Swirling Void.
There, however, demons were already waiting for them...
The torture that his torturers - Tichondrius, Balnazzar, Detheroc, Mal'Ganis and Varimathras - prepared for the orc shaman was nightmarish. They tore apart his physical body piece by piece, keeping his spirits in perfect condition. Soon Ner'zhul began to beg for death. Kil'jaeden agreed to give him what he wanted on the condition that he agreed to serve the Legion as a new weapon.
The Phantom Lords - Warcraft III: Reign Of Chaos
The orc agreed to the offer. The demon killed him and then resurrected him, giving him powers unavailable to him before. The Overlords fused his disembodied soul with specially crafted armor and the mighty Frostmourne Rune Sword. All of this was encased in a hard block of ice to trap and control Ner'zhul.
The Lich King, for that is what he was now, was promised to receive his freedom if he was loyal to the Legion.
However, he knew that those were empty words. Therefore, he slowly began to put together his own escape plan. In the meantime, all of Ner'zhul's subjects had also undergone a physical transformation. The Undead army was ready.
Kil'jaeden revealed his plan to his new servant. His task would be to weaken Azeroth by sending a deadly plague, turning humans into obedient undead servants who would weaken the defenses of this world before the arrival of the Legion. The Dark Demon did not fully trust the Lish King. He decided that the Phantom Lords would accompany him on his expedition to Azeroth. With a massive expenditure of power, they managed to create a small portal between the Whirling Void and Azeroth. After passing through, the Fox King's ice block landed on a glacier in the frigid land of Northrend. Upon impact, the Ice King Lish's prison changed shape and began to resemble a throne.
As the Phantom Lords built a fortress around the Frost Throne, King Lisz tested his power. He had to be careful, for Kil'jaeden did not want the world to learn of the new threat prematurely. The first targets of the new lord on Northrend became the Wendigo and the Ice Trolls. Next came the mighty tribes of Vrykuli. One by one, each creature was slaughtered by the servants of the Lish King, only to be reborn as a mindless, undead being. In the meantime, he began to work on the scourge of the undead. He could control it with the power of his mind and as a test, sent it to a small human village. After 3 days, all of its inhabitants were dead. Shortly after, they rose again, this time as undead.
The Lich King has never felt so powerful! Every new soul, every new body raised his power to levels he never even dreamed of.
The Ghostly Lords were not idle either, they built a true fortress around the Frost Throne to serve as the base for their entire campaign against Azeroth. Kil'jaeden's plan slowly came to fruition. He ordered King Lish to expand his jurisdiction, he was to conquer all of Northrend. The Lish King did everything the Dark Demon wanted from him, but he had no loyalty to him. He was quietly looking for a way to get out from under his control. He knew that the smart and cunning Phantom Lords were the biggest threat. However, their power could not compare to the power the Lich King had gained. He allowed them to believe that he was their prisoner, that they had control over him. The hunter began to watch his game. When he finds its weak points, he will attack.