Quotes about demon
page 2
Source: Touch the Dark

“The demons were scary, but girls - Well, girls are really terrifying”
Source: Lord Loss

Source: The End of Faith: Religion, Terror, and the Future of Reason

“This is not some silly game… This is life and death Angels and demons.”

“You see demons in the eyes of the world, and the world sees a bottomless pit in yours.”
Source: Challenger Deep
“There is nothing to fear except the power you give to your own demons.”
Source: The Red Necklace

“What happens in the demon realms stays in the demon realms,” said Jace.”
Source: City of Heavenly Fire

Source: Story People: Selected Stories & Drawings of Brian Andreas
Source: A Rogue's Proposal

“There's no room for demons when you're self-possessed.”
“Conclusion 2:
There's nothing more demonic than two bored twins.
~Signed Tamaki”
Source: Ouran High School Host Club, Vol. 2

“Whenever a thing is done for the first time, it releases a little demon.”
Quoted on the web sans source. Not in the complete Poems. A 2006 self-help book attributes it verbatim to Dave Sim (see below) sans source. A 2009 reprint of Poems: Second Series mentions it in the introduction sans source (thus probably taking it from the unsourced web quote). No earlier attributions found.
Compare to a quote sourced to Dave Sim: "Anything done for the first time unleashes a demon." (Cerebus #65, 1984)
Misattributed
“Lothaire betrayed us! Again.” -Random demon.”
Source: Dreams of a Dark Warrior

Source: The Vision of the Anointed: Self-Congratulation as a Basis for Social Policy

Source: Walden and Other Writings
Source: Tempt Me at Twilight

“Keep a demon busy, I thought. Right. Maybe he fancies a game of Tiddlywinks.”
Source: The Red Pyramid
Source: The Art of Racing in the Rain

“Tools are neither demonic nor divine. It’s all about who wields them.”
Source: UnDivided

“You cannot simply ask whether people look like their demon grandfather!”
Source: Nothing but Shadows
“When we did art with the kids, the demons would lie down.”
Source: Plan B: Further Thoughts on Faith
“My demon's a girl? Gideon said, astonished.”
Source: The Darkest Lie

“Everywhere I looked, demons of the future [were] on the battlegrounds of one’s emotional plane.”
“This was full when I left. Demon, did you eat some of my toothpaste?”
Source: Demon from the Dark
Source: The Darkest Whisper
“What is the world coming to, when you can't even trust a rogue vicar and her demon lover?”
Source: Just Another Judgement Day
“You're facing your demons. You'll come out stronger.”
The One I Left Behind