Instead of a collection of new roles, Ultimate Werewolf Artifacts gives each player an Artifact card. Each Artifact has some sort of special power attached. However, once the player decides to use that power, it becomes public knowledge, so everyone in the village knows that player has that new power. Some powers are relatively benign, like the Mask of the Spellcaster, which lets that player target a player who must not speak for a day. Other powers divulge information, like the Eye of the Beholder, which allows its wearer to wake each night with the Seer to see her selection and the identity of that selection. Still other powers can protect the holder, hurt specific players, and impact the village in other ways. There are 40 Artifact cards in Ultimate Werewolf Artifacts, each of them with a unique power.
One of the great things about this expansion is that it works with the version of werewolf you use today, whether it's a commercial version or a print and play set of cards, or even a deck of cards (though I highly recommend against that, for obvious reasons).
The Artifacts expansion will be available for the first time this October at Essen Spiel in the Bezier Games booth (#5-100), and you can preorder it directly from Bezier Games at http://www.beziergames.com.