The Frozen Heart
The secrets of the Dark Cathedral were buried forever, and those who participated in that operation, including myself, later discussed how we should have seized the opportunity to destroy the Lich King. I have no regrets; if a victory achieved at the cost of Fordring's sacrifice isn't a victory, then so be it. The Argent Crusade owes the Forsaken a debt. And with Arthas's Heart gone, there will never again be any hope of saving this fallen Prince.
"Explore his inner self?" Nathanos smiled coldly. "Do you want me to see just how evil his heart can be?"
"Go to Icecrown Citadel. There's a forgotten cave beneath the fortress. Jump in, and watch out for the ice in the water." The boy waved his hand... and then vanished completely.
Venturing deep into Icecrown Glacier was dangerous, and approaching Icecrown Citadel would be tantamount to placing oneself right under the Lich King's nose. Nathanos wondered if he truly wanted to do something so foolish. He simply chuckled, summoned his skeletal Gryphon, and headed in the opposite direction from the Argent Crusade camp. The boy's choice of words was quite deliberate: "Forgotten Caves"? The Lich King would allow the Scourge to sweep across the entire world; could there really be places he had forgotten?
He slowly made his way to the edge of the cave, creaking and groaning as he gazed at the icy cavern shrouded in mist a thousand feet below. There was no sound; it seemed like a trap. The surrounding space was vast, filled with stone pillars of Saronite, above which stood the steps leading to the Icecrown Citadel. Logically, the Lich King shouldn't have left such a place in a fortress, yet it was neither guarded nor used as a training ground for new recruits.
Or perhaps to conceal something, Nathanos's eyes were fixed on the ground below, and one foot had already stepped out.
Simply falling like that might not have killed him: his body was just a shell, and the soul cannot be killed by physical means. But what was the point? Why was he here? Arthas's humanity had reverted to its childhood form, and he had found him, telling him to explore the Prince's heart.
Why should I do this? I should be thinking about how to thwart the Lich King's plot, not taking such a huge risk to experience a high-altitude fall.
After a brief moment of hesitation, the Witherer pushed forward with his other foot, which was still on the ground. Even when every inch of his body was in mid-air, he still couldn't understand why his thoughts and actions were always opposite after death.
Its form began to change; its cloak and armor became ethereal, its crimson eyes grew even more fanatical, the Witherer's legs transformed into black mist as it rapidly advanced downwards into the cave.
I don't know which idiot said it, but the lower you go, the darker it gets. Yet, the exit at the bottom of the cave seems to be shimmering with light. After passing through, Nathanos immediately realized he had entered a sea of crystal. It was filled with brightly colored crystals, and there were also lakes formed from fresh water. It was chillingly cold, yet the lakes weren't frozen. How strange!
Nathanos reverted to his original form, a transformation that wasn't instantaneous; each transformation left him briefly weakened. He used this recovery time to observe the area.
The word "forgotten" is both fitting and somewhat inappropriate to describe this place, because creatures still inhabit the cave. Tall, distorted Faceless Ones roam aimlessly, not even attacking Nathanos after he entered.
Note the ice in the water. The boy's last words before disappearing seem to be a reminder to Nathanos to focus on the lake, because due to the light, the water's color and the crystal's color are mixed together, both appearing purple, making it difficult to see what's underwater. And there's no ice...
If it's not on the surface, then it must be underwater. The Witherer plunged into the lake to see if his idea was correct.
The situation is different underwater. Hidden in the mud at the bottom of the water are many broken skeletons, some scattered items and clothing, and... crystals?
Nathanos noticed a crystal floating in the center of the lake, emitting a deep blue hue unlike any other crystal. Was this the boy talking about? It did resemble ice, but what made it different? Nathanos approached and understood everything.
This thing wasn't crystal at all, but some kind of organ encased in ice. The Witherer reached out to touch it, and just a fingertip away, a sharp pain shot through him, as if his hand had been chopped off, but Nathanos saw no wound. When he focused again, he heard the voice of a boy nearby drifting in.
"Don't touch it, you really shouldn't have done that."
Nathanos emerged from the water, approaching the little ghost standing on the shore. "Why? Why is his heart here?" It was the most vital organ in the human body. Nathanos recognized it; he wasn't a fool. The boy was born from Arthas's humanity, and he had led him to a heart. There was no doubt who the heart belonged to!
"You know what?" the boy looked at the soaking wet Nathanos, "I saw him throw it away, throw it here. He said he never needed it again because it only made him weak..."
Pain and despair nearly overwhelmed Nathanos; he simply couldn't imagine what kind of person could rip out his own heart and discard it. The Prince had always been cruel, and he was no exception, even towards himself.
"You really shouldn't have touched it. Even though it was so close, he already knows. He knows someone found his heart. Arthas abandoned it, but that doesn't mean he doesn't care. He will never allow anyone to use it against him. He'll be here soon; you need to get out of here quickly." A small portal appeared behind the boy. "Go through it and you'll be back above the cave."
Why do I need to know all this?
"If the Lich King stood before you, and you had one chance to kill him, would you seize the opportunity without hesitation?"
Nathanos was taken aback by the boy's sudden question and fell silent, staring intently at the portal.
"That's why I'm here, and that's why I'm looking for you, Nathanos." The ghost's voice struck the heart of the Witherer. "You can promise your people revenge against the Lich King, you can swear behind your beloved's back that you'll never be swayed by emotions again, but what about when you actually face them? The memories of the past expose your weaknesses, your vulnerabilities are so obvious. Now it's time to end all of this. We will meet again, he will come for you, he will come for you sooner or later."