Ner'zhul and his followers entered the Twisting Nether, the ethereal plane that connects all of the worlds scattered throughout the Great Dark Beyond. Unfortunately Kil'jaeden and his demonic minions were waiting for them. Kil'jaeden, who had sworn to take vengeance on Ner'zhul for his prideful defiance, slowly tore the old shaman's body apart, piece by piece.

Kil'jaeden kept the shaman's spirit alive and intact, thus leaving Ner'zhul painfully aware of his body's gross dismemberment. Though Ner'zhul pleaded with the demon to release his spirit and grant him death, the demon grimly replied that the Blood Pact they had made long ago was still binding, and that Ner'zhul still had a purpose to serve.

The orcs' failure to conquer the world for the Burning Legion forced Kil'jaeden to create a new army to sew chaos throughout the kingdoms of the Azeroth. This new army could not be allowed to fall prey to the same petty rivalries and infighting that had plagued the Horde. It would have to be merciless and single-minded in its mission. This time, Kil'jaeden could not afford to fail.

Holding Ner'zhul's spirit helpless in stasis, Kil'jaeden gave him one last chance to serve the Legion or suffer eternal torment. Once again, Ner'zhul recklessly agreed to the demon's pact. Ner'zhul's spirit was placed within a specially crafted block of diamond-hard ice gathered from the far reaches of the Twisting Nether.

Encased within the frozen cask, Ner'zhul felt his consciousness expand ten thousand-fold. Warped by the demon's chaotic powers, Ner'zhul became a spectral being of unfathomable power. At that moment, the orc known as Ner'zhul was shattered forever, and the Lich King was born.

Ner'zhul's loyal death knights and Shadowmoon followers were also transformed by the demon's chaotic energies. The wicked spellcasters were ripped apart and remade as skeletal liches. The demons had ensured that even in death, Ner'zhul's followers would serve him unquestioningly.

When the time was right, Kil'jaeden explained the mission for which he had created the Lich King. Ner'zhul was to spread a plague of death and terror across Azeroth that would snuff out human civilization forever. All those who died from the dreaded plague would arise as the undead, and their spirits would be bound to Ner'zhul's iron will forever.

Kil'jaeden promised that if Ner'zhul accomplished his dark mission of scouring humanity from the world, he would be freed from his curse and granted a new, healthy body to inhabit.

Though Ner'zhul was agreeable and seemingly anxious to play his part, Kil'jaeden remained skeptical of his pawn's loyalties. Keeping the Lich King bodiless and trapped within the crystal cask assured his good conduct for the short term, but the demon knew that he would need to keep a watchful eye on him. To this end, Kil'jaeden called upon his elite demon guard, the vampiric dreadlords, to police Ner'zhul and ensure that he accomplished his dread task.

Tichondrius, the most powerful and cunning of the dreadlords, warmed to the challenge; he was fascinated by the plague's severity and the Lich King's unbridled potential for genocide.