Silver, the lunar metal, is a werewolf’s great weakness.
As the movies show, the one weakness of any werewolf is silver. A werewolf has no defense against what they call "Luna's metal". Next to silver, the most dangerous threats to garou are fire, radiation, and the attacks of other supernatural creatures. All of these forces deal powerful and lasting damage, called aggravated damage.
The garou heal incredibly quickly in most of their forms, but aren’t immortal. Wounds inflicted by silver weapons do not heal as quickly. A silver bullet is as dangerous to a werewolf as a lead slug is to a human. Of course, in neither case is an instant kill guaranteed — but with a good shot through the heart, there’s little a werewolf’s incredible healing ability can do.
If a homid or lupus werewolf is in her breed form, an attack with a silver weapon does nothing special. It causes bashing or lethal damage as appropriate and can be soaked as normal — that the weapon is silver does not factor in to the damage. Just touching silver causes one level of aggravated damage per turn of contact, unless the werewolf is a homid or lupus who is in her breed form.
In any other form, a werewolf cannot soak damage from silver without a gift or fetish, and the damage taken is aggravated. A successful attack always deals one point of damage, even if the attacker rolled no successes for damage. Metis do not have safety of a breed form to shield them from the ravages of silver. They take unsoakable aggravated damage from silver in any form.
Some Garou carry silver, usually in the form of weaponry such as klaives. Doing so, however, comes with a price. The Garou’s natural allergy to silver causes a reduction in his effective Gnosis. This loss remains in effect in all forms, including the character’s breed form. For every object made of or containing silver that a werewolf is carrying, he loses one effective point from his Gnosis rating. More potent objects will cause the individual to lose more. Luckily, this effect is only temporary, and it lasts only a day after the silver is discarded. For every five silver objects a pack carries, all its members suffer this reduction. In addition, carrying too many silver objects, especially bullets, may cause a loss of Honor or Wisdom for the pack.
No modern werewolf knows how it was that humanity learned the secret of silver, but they know the result all too well. Some time ago, toward the end of the War of Rage, humanity decided it had lived in fear of the night long enough. Somehow, humanity gained not only the courage to fight the Garou but the means to do it. Still damaged from the War of Rage and fractious in any event, the Garou fell back, and a great and momentous argument began. The werewolves fought for months, but eventually reached an agreement called the Concord.
It’s difficult to fashion a weapon out of silver, but a skilled blacksmith or gunsmith can make such a weapon. Those who know of the Garou’s existence know to keep silver weaponry close. Some items can be plated with silver, rather than being made entirely of silver. These items deal damage as though they were silver weapons, but the plating is ruined after a couple of blows.
- Werewolf: The Apocalypse 20th Anniversary Edition, p. 31-32, 38, 146, 256, 259