SG: Therianthrope Vulnerabilities
Depending on your campaign, you may decide weres have particular vulnerabilities. These might work best as aspects that can be invoked against shape shifters in particular. These are options you can choose to use, or not. We recommend using the Silver vulnerability for the cursed and ferals, with cold iron being the main vulnerability for primals.
A lot of fiction indicates silver is especially dangerous to weres. You may decide in your game that it is effective against one or all types of shape shifter. When implementing the vulnerability, allow the silvered item to have the aspect, Silvered, and allow the first invocation in a scene to be free. This can be used to inflict bonus damage on a successful attack, or as a bonus to actions to restrain the were. You may also determine that consequences inflicted by silvered weapons cannot be reduced by Shifter Regeneration (see the Physique stunt).
Option: Cold Iron
This is perhaps an option best used for shape shifters whose home realm is Faerie, such as primal shifters. It acts in the same way as silver, above.