Maybe hard to find a thread title that makes sense, but here's the deal.
My players have found an item (
the heart of an ancient green dragon per Medieval Melodies blog, if you're interested) that provides plenty of cool benefits. The original description, however, says you turn Lawful Evil and that this "may" turn you into a NPC under the control of the DM.
Now, I personally use "no evilz" in my campaign. Making an exception here doesn't feel right. Which means that if I follow the suggested rule that makes the item unusable by player characters. Thing is, I don't
want to uselessness the item this way.
We're gamers at heart so using dice feels natural to us.
What I do want is: the cost of donning the item is
a risk of becoming evil and thus possibly facing character retirement. I want only those players willing to risk having to switch characters for story reasons to apply for this item. If a player would be upset or angry he or she should simply pass.
Now then: what precedent in the history of D&D is there for this kind of die roll?
Making it a specific skill check or save feels unfair - there's nothing about this item that says it should only be usable to certain characters (except draconic sorcerers I guess). I don't want to pretty much exclude half the group based simply by the class or ability choices they made more than a year ago at level 1.
Instead I'm looking at 5E and seeing how Death saves are equal to all (or mostly all) characters. The risk of Wish turning bad is also a set percentage.
Is there any AD&D or Pathfinder (or any other edition) specific mechanism that would cover what I'm trying to do here.
Fair warning: My inclination is to make it a straight 15% risk. That is, rolling d100 (so no d20-roll abilities come into play) and if you get 86-00 you turn Lawful Evil and one thing is certain: the item and its benefits are lost. So this thread is more of a "let's ask ENWorld so I'm not missing out on something cool" thread.
(I would say "your previous flaws, traits and bonds are replaced" and even "your character is retired" but since the party is level 16 I am leaving this part open. After all, using Wish to reverse the alignment change feels entirely reasonable. Just to take the obvious example - I would not be surprised if crafty players can come up with other spells and effects as well)
My question again: do you recall any "class-neutral" rule or scenario from previous decades of D&D where a similar character-dooming decision is made?