It was Quirrell.
"You!" gasped Harry.
Quirrell smiled. His face wasn't twitching at all.
"Me," he said calmly. "I wondered whether I'd be meeting you here, Potter and surprisingly, Walter".
"I should've guessed, I felt a strange presence around you, but you didn't seem the type, so I let my guard down", Key admitted.
"I should've expected that from a fae", said Quirrell.
"But, I was so sure it was Snape, and Key why didn't you tell me", said Harry.
"Severus?" Quirrell laughed, and it wasn't his usual quivering treble, either, but cold and sharp. "Yes, Severus does seem the type, doesn't he? So useful to have him swooping around like an overgrown bat. Next to him, who would suspect p-p-poor, st-stuttering P-Professor Quirrell?"
"You put up a good act, wait, but the Quidditch match", said Key. "Didn't Snape try to kill Harry, Hermione say him?"
"No, no, no. I tried to kill Harry. Your friend Miss Granger accidentally knocked me over as she rushed to set fire to Snape at that Quidditch match. She broke my eye contact with you. Another few seconds and I'd have got you off that broom. I'd have managed it before then if Snape hadn't been muttering a countercurse, trying to save you." Quirrell revealed.
"Snape was trying to save me?" asked Harry.
"Whoa! I misjudged him a lot", said Key.
"Of course," said Quirrell coolly. "Why do you think he wanted to referee your next match? He was trying to make sure I didn't do it again. Funny, really... he needn't have bothered. I couldn't do anything with Dumbledore watching. All the other teachers thought Snape was trying to stop Gryffindor from winning, he did make himself unpopular... and what a waste of time, when after all that, I'm going to kill you tonight along with you, Walter".
Quirrell snapped his fingers. Ropes sprang out of thin air and wrapped themselves tightly around Harry and Key gets trapped in a ball of fire.
"I knew you two would be trouble, especially after Halloween", said Quirrell.
"You let the troll out", said Key.
"Very clever, Walter, yes", said Quirrell. "Unfortunately, while everyone else was running around looking for it, Snape, who already suspected me, went straight to the third floor to head me off -- and not only did my troll fail to beat you to death, that three-headed dog didn't even manage to bite Snape's leg off properly".
"So, that explains what happened. I was wrong all along", said Harry, feeling sad
"It's okay, Harry, it's not your fault, I wouldn't tell him, but Snape is the worst and suspicious", Key reassures Harty.
"What a sweet cousin", said Quirrel. "Now, wait quietly, Potter and Walter. I need to examine this interesting mirror".
Harry and Key figure out the mirror in front of Quirrell is the Mirror of Erised.
"This mirror is the key to finding the Stone," Quirrell murmured, tapping his way around the frame. "Trust Dumbledore to come up with something like this... but he's in London... I'll be far away by the time he gets back..."
Harry gives the signal to Key.
Key winks back at Key.
"I saw you and Snape in the forest -- " Harry blurted out.
"Yes," said Quirrell idly, walking around the mirror to look at the back. "He was on to me by that time, trying to find out how far I'd got. He suspected me all along. Tried to frighten me -- as though he could, when I had Lord Voldemort on my side..."
Key looks at the mirror of Erised, then noticed something sparkly, in a whisper "No way!"
Harry noticed Key looking shocked, and he tries to get her attention, even though Key turns to Harry, she just shakes her head.
Harry mouths 'please' to Key.
Key mouths 'The mirror, the key to our victory is the mirror, only you and I can see it' to Harry and smiles.
Harry mouths confused 'Only you and I can see''.
Quirrell came back out from behind the mirror and stared hungrily into it.
"I see the Stone... I'm presenting it to my master... but where is it?" asked Quirrell.
"But Snape always seemed to hate me so much", said Harry.
"Oh, he does," said Quirrell casually, "heavens, yes. He was at Hogwarts with your father, didn't you know? They loathed each other. But he never wanted you dead."
Harry signals Key.
"But I heard you a few days ago, sobbing -- I thought Snape was threatening you..." replied Key.
For the first time, a spasm of fear flitted across Quirrell's face.
"Sometimes," said Quirrell, "I find it hard to follow my master's instructions -- he is a great wizard and I am weak--"
"You mean he was there in the classroom with you?" Harry and Key gasped.
"He is with me wherever I go," said Quirrell quietly. "I met him when I traveled around the world. A foolish young man I was then, full of ridiculous ideas about good and evil. Lord Voldemort showed me how wrong I was. There is no good and evil, there is only power, and those too weak to seek it... Since then, I have served him faithfully, although I have let him down many times. He has had to be very hard on me." Quirrell shivered suddenly. "He does not forgive mistakes easily. When I failed to steal the stone from Gringotts, he was most displeased. He punished me... decided he would have to keep a closer watch on me..."
Quirrell's voice trailed away. Harry was remembering his trip to Diagon Alley -- how could he have been so stupid? He'd seen Quirrell there that very day, shaken hands with him in the Leaky Cauldron.
Quirrell cursed under his breath.
"I don't understand... is the Stone inside the mirror? Should I break it?" Quirrell sounds annoying.
'The mirror is the key, the stone, Key could see it', thought Harry, and started putting two and two together.
"What does this mirror do? How does it work? Help me, Master!" Quirrell talks to himself.