So why did Ner'zhul choose Arthas, of all people, to become his champion? Perhaps that spark of Ner'zhul saw something of himself in the young prince, the same drive to do what was right for his people and his kingdom, regardless of cost. Regardless of his motivations, Ner'zhul chose Arthas as the body for his sprit, the housing for the Lich King. The two fused into one creature the moment Arthas placed the Lich King's helm on his head -- both Arthas and Ner'zhul still present, but two small pieces of one greater being.
The Lich King continued to grow in power until he was ready to strike with full force upon the rest of the world, bringing about the Wrath of the Lich King expansion. This also brought about a lot of general confusion by the player base as to how much of Arthas, or Ner'zhul, remained inside the Lich King, and how much was just the Lich King himself. In the novel Arthas: Rise of the Lich King by Christie Golden, the events that play out take place just before Wrath of the Lich King's launch, and explain much of the life of Arthas, and how he came to follow the path that eventually led him to the Frozen Throne.
However, both the prologue and the epilogue of the novel are events that people don't seem to take into account. In the prologue, Arthas dreams. He is sitting in a great hall at a table with an orc, and a young, sickly boy. The rest of the novel and Arthas' life play out in full, and in the epilogue we are once more taken to that table somewhere in the Arthas' mind.
The orc is Ner'zhul, or what is left of Ner'zhul's spirit, and he took a moment to show Arthas visions of events yet to pass. The Horde and Alliance, fighting each other and then fighting together against him, the rebuilding of Quel'Thalas, a brief vision of the Emerald Dream. Arthas looked at the boy, and realized something -- the boy was himself, the last vestige of his own humanity, the ability to love, to care, to grieve. The boy began to cry as Arthas recognized him, and said that there must still be some good within Arthas, if that little boy still existed inside of him. The boy told him that it didn't have to be too late, indicating that there was still a chance for Arthas to redeem himself.
And Arthas replied, "But it is." The boy in the dream, the last spark of goodness retained within Arthas is utterly destroyed by Arthas' hand. All weakness, all second-guessing and hesitation now gone, Arthas was now free to scour the world and cleanse it of its humanity in much the same fashion. Ner'zhul was pleased, and congratulated Arthas -- and abruptly met with the same fate as the little boy.
This was the moment that Ner'zhul's spirit died. This was also the moment that Arthas' humanity died, and all that was left was the Lich King, imbued with the soulless spirit of Arthas, the side of him that showed no weakness, no regret, no compassion, no grief. It could be argued that Arthas himself ceased to exist at this point, but the more logical conclusion is that Arthas went from being a rational human being to a sociopath -- a being with a complete lack of emotion that views the rest of the world as an opportunity to be conquered.
Players argue that the Lich King states in a quest line in Howling Fjord "I was once a shaman," but what they fail to see is the unspoken second half of that sentence.
"But I'm not anymore."
This is what makes the current incarnation of the Lich King a threat that absolutely must be addressed as quickly as possible. The portions of Arthas and Ner'zhul's spirits that held the Lich King and the Scourge back for all of these years between the Third War and present day are absent now; this is why the Lich King chose to strike when he did.
He was not just preparing for attack while sitting around in Northrend all of those years; he was fighting an internal war with himself. Once he won that war and destroyed the basic components that were holding him back, the next step was to strike out and begin the process of Azeroth's domination.
Players also encounter an epic questline in Icecrown -- during a mission to weaken Icecrown Citadel from below, they set off an explosion and fall far beneath the Citadel into a pool of water. In the water is a pulsing crystal, and touching the crystal causes immense pain and another, more interesting result. A voice says, "You really shouldn't have done that." Further investigation reveals a child on the shore named Matthias Lehner, who proceeds to send you on a dizzying array of quests that reveal just what happened with Arthas, and the origin of the strange crystal under the lake.
That crystal is Arthas' heart, which he forcibly removed from his body. From a timeline perspective, I suspect he cut out his heart shortly after the events in Arthas: Rise of the Lich King, and pitched it under the Citadel. Players are sent to Tirion Fordring to report on the strange little boy and the information revealed about the heart, and Tirion sets up a gambit to intercept the heart while it is being transported from the depths below the Citadel to the Cathedral of Darkness above. Tirion has hopes that the existence of the heart is a sign from the Light that Arthas can somehow regain his lost humanity -- but the events of Tirion's Gambit play out differently than expected.
Tirion decides in one fatal moment that the only pieces of humanity Arthas has left are merely shadows from the past, and runs the Ashbringer through the crystallized remains of the Lich King's heart. It deals a tremendous amount of damage to Arthas, and players are rushed out before the Lich King can regain enough strength to unleash his fury.
The little boy, Matthias Lehner, is the last remnant of Arthas' humanity -- embodied as a child much like he was in the novel. You see him upon touching Arthas' heart, and once that heart is destroyed you never see him again. It appears that the Lich King ripped out his heart, the boy and his humanity but was unable or unwilling to destroy it, choosing instead to just throw it away. The final killing blow, the destruction of Arthas' humanity was not from Arthas himself, but Tirion Fordring.
Arthas, the Lich King, had to be destroyed. Tirion used the Argent Tournament to train both Alliance and Horde soldiers in an effort to weed out those not strong enough to battle the Lich King face-to-face -- there's no point in sending soldiers to the Lich King if they're just going to die and fuel him with more fodder for his Scourge army. But the opening of the Icecrown Citadel revealed information that was much more important than simply access to kill the Lich King.
Players entering the Halls of Reflection find Frostmourne, the Lich King's sword, curiously unattended. From within the sword, a vision of Uther Lightbringer appears and delivers some startling news: Arthas is nothing more than a dwindling presence in the Lich King's mind, unredeemable. But the Lich King cannot be destroyed. There must always be a Lich King -- even if the Lich King is destroyed, the Scourge will still exist. Only it would be a Scourge without a master, spreading across Azeroth, and killing everything in its path. There must be someone in control, or the Scourge will destroy the world and everything in it.
While the story of Arthas is a sad one, there is nothing left of the prince to be redeemed; nothing left of the Lich King that can be saved. His fate is inevitable, a forgone conclusion and a moment in Warcraft history that will not be forgotten. But who, out of everyone on Azeroth, will step up to the plate and take over the mantle of the Lich King? The answer has already been delivered. Stay tuned next week when I go into the history of the new Lich King, Bolvar Fordragon -- who he is, what he's done with his life, and why, ultimately, he is the only person that can logically take over the mantle of the Lich King and bring some sort of tentative peace to the world of Azeroth.