There's a big fat hint in chapter 20. It's compatible with Monroe!Quirrell being an unpleasant person in the same way Voldemort was, but one of those on each side including the supposedly good one is less likely than the big bad playing both sides.
Here are the relevant quotes:
..."Other people have done huge amounts for me!" Harry said. "My parents took me in when my parents died because they were good people, and to become a Dark Lord is to betray that!"
Professor Quirrell was silent for a time.
"I confess," said Professor Quirrell quietly, "when I was your age, that thought could not ever have come to me."
"I'm sorry," Harry said.
"Don't be," said Professor Quirrell. "It was long ago, and I resolved my parental issues to my own satisfactio
Edit: New thread posted here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 86. The previous thread has long passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: