The Avada Kedavra burst from Quirrell's wand tip.
That streak of green was fast as lightning, shooting straight at Iain in the distance.
"Not good! Ambush!"
Iain had been crawling on the ground, and the instant he saw that green flash, his body moved before his brain did.
So he rolled on the spot, shoulder hitting dirt, back scraping across the ground, his whole body spinning like a marble flicked sideways, chaining invincibility frames as he rolled twice to the side.
And somehow, incredibly, that Killing Curse, a spell with no real counter-curse, actually missed because Iain dodged it like that.
The green light brushed past his ear and slammed into the tree behind him. Bark exploded, wood chips flew everywhere, and a scorched hole was left in the trunk.
"?????"
Quirrell froze on the spot.
"Murder! Someone's trying to illegally strip out my plus-thirteen enhanced organs!" sprawled on the ground, Iain looked up and saw Quirrell standing beyond the trees.
The man's purple turban, dark robes, and corpse-pale face made his identity instantly obvious.
"Damn it! It's Voldemort's human vessel!" Iain blurted out, recognizing the future Defense Against the Dark Arts professor. In sheer panic, he yanked his wand out of his trousers.
"??????"
At that moment Quirrell was still stunned, his wand hand going rigid. Not because of what Iain had shouted, but because his Avada Kedavra had actually been dodged.
He had lived this many years and had never once seen someone evade a Killing Curse by rolling on the ground.
Rolling.
A little wizard rolling on the dirt had dodged his Avada Kedavra?
For a moment, Quirrell had no idea whether he was just that incompetent or whether the boy's luck was simply monstrous.
"What are you doing!"
That shrill voice came from the back of Quirrell's head, like metal scraping broken glass, stabbing at the eardrums. "You can't even hit one crawling brat!"
Clearly, even the Dark Lord could not comprehend what he had just seen.
Quirrell's body trembled. His voice shook. "M-my lord, he dodged it…"
"I saw that! Useless trash!" The voice sharpened even further. "Cast again! Now!"
Quirrell hurriedly raised his wand, hand trembling, tip aimed at Iain.
His lips shook. He had not even gotten the curse out before Iain had already scrambled to his feet. The young wizard moved so fast Quirrell's eyes could barely track him.
One hand held the wand he had just pulled, still warm from its very unfortunate hiding place. The other braced against the ground as he twisted up, knees bent, body pitched forward in a low, spring-loaded stance.
"Lumos!"
Iain's voice was not loud, but every syllable came out crisp and clear.
Green light gathered on his wand, like some deep subterranean glow surging upward. It was greener than Quirrell's Killing Curse from a moment ago, darker, colder, deader.
"What is he doing?"
Quirrell stared at that green light, dumbfounded.
Lumos?
A lighting charm?
Had this little wizard been scared stupid?
At a life-or-death moment like this, the boy had pulled out his wand and cast the first spell every first-year practically knew, a harmless lighting charm with no offensive power at all?
"So he really is just a kid."
Quirrell almost sneered.
But.
The curve of mockery never had time to finish forming.
His skull nearly exploded.
"Idiot! Run!" the shrill voice screamed, tearing at his ears. "That's the Killing Curse!"
The Dark Lord's instincts, at least, were still sharp.
"My lord! What are you talking about!"
Quirrell's half-formed smile froze on his face.
His pupils contracted violently. His mouth opened, trying to say something.
But Iain gave him no chance.
The green light on his wand had already gathered to its limit, like a star compressed to the absolute brink. The instant it released, it burst outward in a flood of radiance. The green light did not fire as a single beam. It spread like a curtain, a whole screen of light, crashing down over him.
"No!!!"
Unable to understand what he was seeing, Quirrell did not even have time to raise his wand and answer with a curse of his own.
It happened in an instant.
The green light slammed straight into him, and the effect was like pouring acid over a wax statue.
Sizzle. Sizzle. Sizzle.
As his soul shrieked, the skin on his body began to melt, his muscles dissolved, his bones crumbled, as though he had been thrown beneath some sun capable of liquefying everything.
There was no proper scream, not even any real struggle. The whole thing happened too fast, as if someone had pressed fast-forward.
This unfortunate, hateful graduate of Ravenclaw, caught completely off guard, never had the chance to use the many tricks and bits of knowledge he had accumulated. His body simply began to disintegrate inside the green light.
Outside to inside. Top to bottom. From existence to nothing.
It could be said that under Iain's spell, almost every trace of Quirrell's existence was erased.
The tattered remains of the purple turban dropped to the ground, still dissolving. Ash drifted out from the collar and sleeves of Quirrell's robes.
That ash scattered slowly through the air, like a snowfall made of soot.
"Aaaaah!"
The scream continued. Voldemort's remnant soul came tearing out of the ashes.
It was a mass of black smoke, dense as spilled ink, twisting and writhing in the air.
He was in agony.
A thin film of green light crawled over the surface of the smoke, like acid for the soul, continually stripping away whatever held Voldemort's remnant together.
"Quirrell, you useless piece of garbage!" From within the black mist a face could barely be made out. No features, just a vague outline, like a hurried charcoal sketch scrawled on white paper.
"Dumbledore! So this is your doing!!!" The face howled at the sky, voice thick with rage, pain, and a fear rooted so deep it bordered on instinct.
The smoke suddenly collapsed inward, like a stretched rubber band snapping loose, and shot toward the distant woods.
Voldemort fled so fast Iain's eyes could not follow him. He only saw a black streak cut across the edge of the sky and vanish behind the tree line.
After all, Iain was still only a newly awakened little wizard.
He did not have time to cast a second Lumos.
The green light on his wand went out the instant Voldemort's remnant soul escaped, like a candle snuffed by the wind.
"No, seriously, why would Voldemort spawn here?!"
Iain stood frozen in place, still holding the casting stance.
His wand remained pointed at the spot where Quirrell had vanished.
The birds in the woods slowly resumed singing. Wind passed through the treetops, leaves whispering together as if gossiping under their breath, while Iain's emotions remained locked somewhere between shock and trembling disbelief.
"This… this counts, right?"
Only after a long while did he slowly lower his wand and walk toward the pile of things Quirrell had left behind. On the ground there was only a heap of ash, still drifting apart.
That was right. Quirrell was gone.
Dead by misfortune.
Wizard duels were often like that. Even powerful wizards could be erased in an instant by a single mistake.
That was normal.
Perfectly reasonable, really.
It was just that…
"The first-year boss is just… gone?"
The little wizard stood there clutching his wand, overwhelmed by a kind of absurd disbelief.
He had not even fully processed the fact that, just now, he had killed someone.