In a dark cathedral, a mage harnesses the power of demons to enhance her spells. In an alchemical laboratory, a diviner inscribes a scroll of destruction. Meanwhile, a bard and beastmaster seek out the prismatic dragon and golden lion to keep these forces of darkness at bay.

Res Arcana: Lux et Tenebrae adds 4 new Places of Power, 12 artifacts, 4 mages, 4 monuments, and 2 magic items to Res Arcana. It also extends the game to five players, adds scaling rules for fewer players, and introduces two new things: scrolls and demons.