Krishnath
First Post
Actually, I find that the heart of darkness is fairly balanced. It's not overly powerful and it causes a permanent loss of Con. Although, I think it would be wise to make it harder to use by good characters. For example, I would have the users alignment go one step towards evil. And if a good character uses it, the character must make a fort save or become undead (I.e: gaining the undead type and loosing con) in addition to moving one step towards evil on the alignment spectrum. Of course this is just my opinion. 
