The central idea with demons is timing those specific behaviors that make them super dangerous. They'll start hunting way earlier than most ghosts at 70% sanity, and they've got this nasty trick where they can actually hunt at any sanity level which is pretty unique. You'll notice their hunts come faster too since they only wait 20 seconds between attempts, instead of the normal 25 seconds that other ghosts take.

Something really important to watch for is how smudge sticks work differently against them. When you light one it only keeps them quiet for 60 seconds, not the usual 90, so you need to adjust your timing. The good news is crucifixes work better, covering 4.5 to 7.5 depending on tier, but that actually makes optimal placement trickier since you need to think about larger spaces.

Other ghosts might seem scarier on paper, like yokai hitting 80% near talking or thaye starting at 75%, but demons are consistently aggressive which makes them more predictable in a weird way. If you're seeing really frequent hunts especially early on and your smudge stick protection seems to wear off faster than normal, you're probably dealing with a demon. Keep track of those cooldowns and always be ready for a hunt even when sanity seems fine.