Does Whispers of Doom Stack?

Can anyone tell me if this passive stacks? If say 3 people in party have it, can mobs then have 3 extra curses? or is this capped by 1 extra curse? So if thats true would that mean only 1 person in a party would then benefit from having it?

My understanding is that the last curser's status wins. If someone who can cast three curses gets overridden by someone who can only cast one curse, the one curse wins. Three curses are removed replaced by the one.

Your example, where multiple people each can cast two curses would simply have the last person's curses override the previous person's.

I'm about 95% sure they won't stack. I believe anyone who has extra curses can use as many curses as they can (so if everyone has 3 curses, then they can all curse monsters up to 3 times, even adding on to curses from other people) but if someone with only one curse then curses, it will override all three curses and just be the one....if that makes sense

Thanks guys, much appreciated