By Rupert Watters (r.watters@dial.pipex.com)
The effect of putting them on is outwardly similar to wearing a normal pair of sunglasses. However, when the lenses are rubbed with a cloth or the like that has absorbed some blood, and then worn, the world about the viewer seems to become shadowy and indistinct. All things appear fleeting and dreamlike, and time seems to jerk, rather than flow.
The advantage of these glasses is the wearer no longer perceives those around him as "real," and therefore has no compunction about drinking their blood, etc. Also, once the glasses are removed, the memories fade as if a dream and the wearer cannot recall his actions during the period he wore the glasses.
After three nights of near continuous usage, the wearer will become deeply attached to the glasses, believing the world of reality to be some dreadful, visceral nightmare, from which his glasses shield him and will become paranoid over their ownership, gaining that as a Derangement. He also acquires the Derangement that he no longer values human life, effectively reducing his Humanity to around 2 - 3.
These effects are reversible, if the wearer goes "cold turkey" abandoning the glasses for several days; there is a chance he will regain some of his Humanity. In order to succeed, the wearer must make a Humanity check (using his original Humanity, prior to acquiring the above derangements) for each day he wore the glasses (minimum of three), against a difficulty of the worst act (according to the characters hierarchy of sins) he committed during the period for which he wore the glasses. If all the checks succeed, the character returns to his original Humanity. Otherwise, various degrees of success will regain various amounts of Humanity (Storyteller's discretion). If any of the checks are botched, the character immediately drops to 0 Humanity, with all the consequences.
Based on the story Masquerade of A Dead Sword, by Thomas Ligotti