From the Novel : “Hello, Arthas.”
Deep and sinister, the voice had changed, but not as much as the kaldorei’s body. It was still the
same pale lavender hue, etched with the same tattoos and scarifications. But the legs, the wings, the
horns…Arthas immediately understood what must have happened. So that was why Illidan had
become so powerful.
“You look different, Illidan. I guess the Skull of Gul’dan didn’t agree with you.”
Illidan threw back his horned head. Dark, rich laughter rumbled from him. “On the contrary, I have
never felt better. In a way, I suppose I should thank you for my present state, Arthas.”
“Show your appreciation by stepping out of the way, then.” Arthas’s voice was suddenly cold, and
there was no trace of humor in it. “The Frozen Throne is mine, demon. Step aside. Leave this world
and never return. If you do, I’ll be waiting.”
“We both have our masters, boy. Mine demands the destruction of the Frozen Throne. It would
seem we are at odds,” Illidan replied, and lifted the weapon Arthas had fought once before. His
powerful hands with their sharp black nails closed on the weapon’s center and he whirled it with grace
and a deceptive casualness. Arthas knew a ripple of uncertainty at the display. He had just finished a
fight with Kael’thas, and while he would have been the victor had not the elf, coward that he was,
teleported out at the last instant, he had been taxed by the battle. There was no hint of weariness in
Illidan’s bearing.
Illidan’s smile grew as he noticed his enemy’s discomfiture. He allowed himself a moment more of
uncannily masterful handling of the unusual, demonic weapon, then struck a position, settling in,
preparing for combat. “It must be done!”
“Your troops are either in pieces or part of my army.” Arthas drew Frostmourne. Its runes glowed
brightly, and mist curled up from its hilt. Behind the blindfold, Illidan’s eyes—much brighter and more
intensely green than he remembered—narrowed at the sight of the runeblade. If the demonicallychanged
kaldorei had a powerful weapon, so too did Arthas. “You’ll end up one or the other.”
“Doubtful,” Illidan sneered. “I am stronger than you know, and my master created yours! Come,
pawn. I’ll dispatch the servant before I dispatch your pathetic—”
Arthas charged. Frostmourne glowed and hummed in his hands, as eager for Illidan’s death as he
was. The elf did not seem at all startled by the sudden rush, and with the utmost ease lifted his doublebladed
weapon to parry. Frostmourne had broken ancient and powerful swords before, but this time, it
simply clanged and grated against the glowing green metal.
Illidan gave him a smirk as he held his ground. Arthas again felt unease flicker through him. Illidan
was indeed changed by absorbing the power of the Skull of Gul’dan; for one thing, he was physically
much stronger than he had been. Illidan chuckled, a deep and ugly sound, then shoved forcefully. It
was Arthas who was forced to fall back, dropping to one knee to defend himself as the demon bore
down on him.
“It is sweet to turn the tables thus,” Illidan growled. “I might just kill you quickly, death knight, if
you give me a good fight.”
Arthas didn’t waste breath on insults. He gritted his teeth and concentrated on battling back the
blows that were being rained upon him. The weapon was a swirl of glowing green. He could feel the
power of demonic energy radiating from it, just as he knew that Illidan could sense Frostmourne’s grim
darkness.
Suddenly Illidan was not there and Arthas lurched forward, his momentum taking him off balance.
He heard a flapping sound and whirled to see Illidan overhead, his great, leathery wings creating a
strong wind as he hovered out of reach.
They eyed each other, Arthas catching his breath. He could see Illidan was not unaffected by the
battle either. Sweat gleamed on the massive, lavender- hued torso. Arthas settled himself, Frostmourne
at the ready for when Illidan would swoop in for a renewed assault.
Then Illidan did something utterly unexpected. He laughed, shifted the weapon in his hands—and
in a flurry of motion seemingly snapped it in two. Each powerful hand now held a single blade.
“Behold the Twin Blades of Azzinoth,” Illidan gloated. He flew up higher, whirling the blades in
his left and right hands, and Arthas realized that he favored neither one. “Two magnificent warglaives.
They can be wielded as a single devastating weapon…or, as you see, as two. It was the favored weapon
of a doomguard—a powerful demon captain whom I slew. Ten thousand years ago. How long have
you fought with your pretty blade, human? How well do you know it?”
The words were intended to unsettle the death knight. Instead, they invigorated him. Illidan might
have had this admittedly powerful weapon for longer—but Frostmourne was bound to Arthas, and he
to it. It was not a sword as much as an extension of himself. He had known it when he first had the
vision of it, when he had just arrived in Northrend. He had been certain of the connection when he laid
eyes upon it, waiting for him. And now he felt it surge in his hand, confirming their unity.
The demon blades gleamed. Illidan dropped down on Arthas like a stone. Arthas cried out and
countered, more certain of this blow than of any he had dealt with the runeblade before, swinging
Frostmourne up underneath the descending demon. And as he knew must happen, he felt the sword
bite deep into flesh. He pulled, drawing the gash across Illidan’s torso, and felt a deep satisfaction as
the former kaldorei screamed in agony.
And yet the bastard would not fall. Illidan’s wings beat erratically, still somehow keeping him aloft,
and then before Arthas’s shocked gaze his body seemed to shift and darken…almost as if it was made of
writhing black, purple, and green smoke.
“This is what you have given me,” Illidan cried. His voice, bass to begin with, had somehow grown
even deeper. Arthas felt it shiver along his bones. The demon’s eyes glowed fiercely in the swirling
darkness that was his face. “This gift—this power. And it will destroy you!”
A scream was torn from Arthas’s throat, and he fell again to his knees. Blazing green fire chased
itself along his armor, seared his flesh, even dulled Frostmourne’s blue glow for a moment. Over the
raw cry of his own torment he heard Illidan laughing. Again the fel fire cascaded over him and Arthas
fell forward, gasping. But as the fire faded and he saw Illidan swooping in for the kill, he felt the
ancient runeblade he still managed to grasp urge him to rally.
Frostmourne was his, and he its, and so united, they were invincible.
Just as Illidan lifted his blades for the kill, Arthas raised Frostmourne, thrusting upward with all his
strength. He felt the blade connect, pierce flesh, strike deep.
Illidan fell hard to the ground. Blood gushed from his bare torso, melting the snow around it with a
slow hissing sound. His chest rose and fell in gasps. His vaunted twin blades were of no use now. One
had been knocked from his grasp, the other lay in a hand that could not even curl around its hilt. Arthas
got to his feet, his body still tingling with the remnants of the fel fire Illidan had hurled at him. He
stared at him for a long moment, branding the sight into his mind. He thought about dealing the
killing blow, but decided to let the merciless cold of the place do it for him. A greater need burned in
him now, and he turned, lifting his eyes to the spire that towered above him.
He swallowed hard and simply stood for a moment, knowing, without knowing how he knew it,
that something was about to fundamentally change. Then he took a deep breath and entered the
cavern."
The TFT cinematic is not canon (it was before the release of the novel) , It was retconed in the novel (since the novel IS canon so)
- - - Updated - - -
Frostmourne moved itself , It has it's own soul according to the book ,"Frostmourne was his, and he its, and so united, they were invincible." ... It said it like that , If it hadn't then we would have had serious lore changes since Illidan would have killed Arthas and that would have meant no BC or WotLK