In the advanced campaign (Sea of Blood) not every player gets an item. Dark Relic says "Play this card when a hero receives a treasure card." So the players draw one item for every blank on one of the four power dies and distribute them. To distrubute them, the players have a look on the item and then one player takes it. The FAQs on page 11 says, that the overlord is not allowed to see the treasure card, before he decides whether to play "Dark Relic" or not. So how does "Dark Relic" work in advanced campaigns and when is it played?

funmasta said:

In vanilla, each hero received a treasure card for each "treasure" in a given chest, thus, the timing of this card was not an issue - the OL could play it as soon as they opened the chest and pick a hero since he knew each hero was getting something.

In the AC it's less clear, since he has to wait until they distribute the item before he knows who's "receiving a treasure card." On the other hand, he can't just fire it off as soon as they roll a treasure result (ie: before drawing the card) because then the heroes know they're getting a Dark Relic when they decide who gets it, and they can pawn it off on whoever can most afford to suck it up.

I would argue that the heroes should draw such treasures, look at them and distribute them without showing the card(s) to the OL. After they have decided which hero(es) are receiving a treasure card, but before they reveal to the OL what it is, he has an opportunity to play Dark Relic. Discuss this ruling with your group before you begin playing. Make sure everyone understands that the heroes should not show the card to the OL until they have decided who gets it, and perhaps even ask them to pause a second after deciding to see if the OL has anything to say. After everyone agrees to this, if the heroes casually reveal the card before assigning it to someone, it's their own **** fault for not waiting to see if the OL had a Dark Relic to play.

Edit: If your group is super-paranoid about the fact that the OL knowing who got the card is "unfair" because he can make an educated guess about what it is, just remember that you can give a shiny suit of magic plate mail to the runner when it first comes out of the chest and then have that hero pass it off to the tank the next time he/she acts. Bluffing is a perfectly valid strategy, if you're really that worried about it.