I barely survived my encounter with a doomsayer, after having got a nasty little idol out of a cursed tomb. I was thinking of bringing it to a church to neutralize it, but nobody seems to show any interest in it, so, I'm now just carrying a creepy stone idol with me.

Is there anything I could do of it ? Also, I assume I won't be harrassed by doomsayers as long as I have it in my inventory, will I ?

When you talk to the Ghost of Ulcaster if you have the Idol of Kozah and the Ancient Armor from Firewine ruins in your inventory, you are supposed to get the vampiric sword.
But I've never got it, & the sword is only good for selling anyway as it is actually a reverse vampire sword. ie It takes your HP & gives it to your enemy.

But no other Doomsayers will come after you if you keep it & try for the sword.

That idol is almost like the the game devs trolling the players :D

You get it after a very nasty encounter, which is usually lethal for a beginner. Then you need to jump through so many hoops before you can make use of it... only to find it makes you a cursed weapon. lol

In summary... just sell it.

I guess I'll keep it stupidly with me, forever and ever and ever, like that white rabbit cage thing in Arcanum...

(Unless the vampiric sword can be used by a very healthy companion to heal another, communicating-vases-like...)