Let me give you a quick rundown about spotting those special sanity drains. Watch your sanity meter during door activity - a yurei drops it 15% instantly when slamming doors outside of ghost events. Regular sanity loss happens slowly from darkness and events, but the yurei hits hard and fast.

Look for exit doors closing without hunts, since that's a dead giveaway only yurei can do that. Monitor any doors really, since full slams paired with sudden sanity drops point straight to our ghost. Regular loss just ticks down gradually from being in the dark or seeing manifestations, nothing dramatic like the yurei's slams.

Good to know about confirmation - drop an incense to lock them in their room for 90 seconds, keep track of those exit doors, and check your sanity meter right after door slams. If you see that instant 15% drop with a door slam but no ghost event, you're probably dealing with a yurei especially if exit doors keep closing on their own during regular gameplay.