Silver
In game terms, all silver weapons cause double their normal damage to those characters and creatures classified as daemons. If a silver weapon strikes a character who is possessed by a daemon, only the daemon will suffer damage, not the host body. Damage is caused not by the edge or type of weapon as much as simply touching silver to these creatures.
Silver weapons also do +1CS damage in addition to any other bonus against certain types of Lycanthropes, shapechangers, and undead.