Their unique ability is Drain, formed from a combination of Dark and Water. Any living creature that comes in contact with their skin rapidly loses energy, becoming exhausted, powerless, and eventually dying. Though the Saturnine are immortal and do not require this energy to survive, they have a tendency to enjoy the experience much in the same way that a mortal would enjoy food. They savor the 'taste' of certain kinds of individual and sometimes descend to Earth merely for the pleasure of the feed.
It should be noted that despite their somewhat intimidating abilities, Saturnine often side with the sorcerers in their battle against the abyss. Like many Planetars, however, they can be unreliable, even dangerous, allies.