Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Harry heard it in the distance, then, the sound of footsteps.

And saw the form (a little hard to see in the mirror) of a person in red robes, coming down the stairs, entering the seemingly empty corridor; accompanied by a small Patronus animal that Harry couldn't quite make out.

The Auror was protected by a blue shimmer, it was hard to see the details but Harry could see that much, the Auror had shields already raised and strengthened.

Crap, thought Harry. According to the Defense Professor, the essential art of dueling consisted of trying to put up defenses that would block whatever someone was likely to throw at you, while trying in turn to attack in ways that were likely to go past their current set of defenses. And by far the easiest way to win any sort of real fight - Professor Quirrell had said this over and over - was to shoot the enemy before they raised a shield in the first place, either from behind or from close enough range that they couldn't dodge or counter in time.

Though Professor Quirrell might still be able to get in a shot from behind, if -

But the Auror halted after taking three steps into the corridor.

"Nice Disillusionment," said a hard male voice that Harry didn't recognize. "Now show yourself, or you'll be in real trouble."

The form of the sallow, bearded man became visible then.

"And you with the Patronus," said the hard voice. "Come out too. Now. "

"Wouldn't be smart," said the gravelly voice of the sallow man. It was no longer the terrified voice of the Dark Lord's servant; it had suddenly become the professional intimidation of a competent criminal. "You don't want to see who's behind me. Trust me, you don't. Five hundred Galleons, cold cash up front, if you turn around and walk away. Big trouble for your career if you don't."

There was a long pause.

"Look, whoever you are," said the hard voice. "You seem confused about how this works. I don't care if that's Lucius Malfoy behind you or Albus bloody Dumbledore. You all come out, I scan the whole lot of you, and then we talk about how much this is going to cost you -"

"Two thousand Galleons, final offer," said the gravelly voice, taking on a warning undertone. "That's ten times the going rate and more than you make in a year. And believe me, if you see something you shouldn't, you're going to regret not taking that -"

"Shut it!" said the hard voice. "You've got exactly five seconds to drop that wand before I drop you. Five, four -"

What are you doing, Professor Quirrell? Harry thought frantically. Attack first! Cast a shield at least!

"- three, two, one! Stupefy! "

Bahry stared, a chill running down his spine.

The man's wand had moved so fast that it was like it had Apparated into place, and Bahry's stunner was currently sparkling tamely at the end of it, not blocked, not countered, not deflected, caught like a fly in honey.

"My offer has gone back down to five hundred Galleons," said the man in a colder, more formal voice. He smiled dryly, and the smile looked wrong on that bearded face. "And you shall need to accept a Memory Charm."

Bahry had already swapped the harmonics on his shields so that his own stunner couldn't pass back through, already tilted his wand back into a defensive position, already raised his hardened artificial hand into position to block anything blockable, and was already thinking wordless spells to put more layers on his shields -

The man wasn't looking at Bahry. Instead he was poking curiously at Bahry's stunner where it still wavered on the end of his wand, drawing out red sparks and flicking them away with his fingers, slowly disassembling the hex like a child's rod puzzle.

The man hadn't raised any shields of his own.

"Tell me," the man said in a disinterested voice that didn't seem to quite fit the rough throat - Polyjuice, Bahry would have called it, if he'd thought that anyone could possibly do magic that delicate from inside someone else's body - "what did you do in the last war? Put yourself in harm's way, or stay out of trouble?"

"Harm's way," said Bahry. His voice kept the iron calm of an Auror with nearly a hundred full years on the force, seven months short of mandatory retirement, Mad-Eye Moody couldn't have said it with any more hardness.

"Fight any Death Eaters?"

Now a grim smile graced Bahry's own face. "Two at once." Two of You-Know-Who's own warrior-assassins, personally trained by their dark master. Two Death Eaters at once against Bahry alone. It had been the toughest fight of Bahry's life, but he'd stood his ground, and walked away with only the loss of his left hand.

"Did you kill them?" The man sounded idly curious, and he continued to draw threads of fire out of the much-diminished stunbolt still captive on the end of his wand, his fingers now weaving small patterns of Bahry's own magic before flicking to disperse them.

Sweat broke out on Bahry's skin beneath his robes. His metal hand flashed downward, ripped the mirror from his belt - "Bahry to Mike, I need backup!"

There was a pause, and silence.

"Bahry to Mike!"

The mirror lay dull and lifeless in his hand. Slowly, Bahry put it back on his belt.

"It's been quite a while since I had a serious fight with a serious opponent," the man said, still not looking up at Bahry. "Try not to disappoint me too much. You can attack whenever you're ready. Or you can walk away with five hundred Galleons."

There was a long silence.

Then the air screamed like metal cutting glass as Bahry slashed his wand downward.

Harry could hardly see it, could hardly make out anything amid the lights and flashes, his mirror's curve was perfect (they'd practiced that tactic before in the Chaos Legion) but the scene was still too small, and Harry had the feeling he wouldn't be able to understand even if he was watching from a meter away, it was all happening too fast, red blasts deflecting from blue shields, green bars of light clashing together, shadowy forms appearing and vanishing, he couldn't even tell who was casting what, except that the Auror was shouting incantation after incantation and frantically dodging while Professor Quirrell's Polyjuiced form stood in one place and flicked his wand, mostly silently, but now and then pronouncing words in unrecognizable languages that would white out the whole mirror and show half the Auror's shielding torn away as he staggered back.

Harry had seen exhibition duels between the strongest seventh-year students, and this was so far above it that Harry's mind felt numbed, looking at how far he had left to go. There wasn't a single seventh-year student who could have lasted half a minute against the Auror, all three seventh-year armies put together might not be able to scratch the Defense Professor...

The Auror had fallen to the ground, one knee and one hand supporting himself as the other hand gestured frantically and his mouth shouted desperate words, the few incantations that Harry recognized were all shield spells, as a flock of shadows spun around the Auror like a whirlwind of razors.

And Harry saw Professor Quirrell's Polyjuiced form deliberately point his wand at where the Auror kneeled and fought the last moments of his battle.

"Surrender," said the gravelly voice.

The Auror spat something unspeakable.

"In that case," said the voice, " Avada -"

Time seemed to move very slowly, like there was time to hear the individual syllables, Ke, and Da, and Vra, time to watch the Auror starting to throw himself desperately aside; and even though it was all happening so slowly, somehow there wasn't time to do anything, no time for Harry to open his lips and scream NO , no time to move, maybe even not any time to think.