Agility Fighter Strain Fighting Art card back/front, from Survivors of Death 1.
Strain fighting arts are special fighting arts that can only be added to the fighting art deck after a specific Strain Milestone is reached. After the milestone is reached, the strain fighting arts can be drawn normally from the fighting art deck. Each strain fighting art has a corresponding card that describes the rules for using it. These count towards your fighting art maximum of 3.
A campaign can have a maximum of 5 strain fighting arts in the fighting art deck. If you would add a 6th strain fighting art, replace an old strain fighting art (remove it from the deck) with the new one instead. If any survivors have the removed fighting art, they still keep it.
When you start a new campaign, if you have earned more than 5 strain fighting arts, you must randomly determine which 5 to add to your fighting arts deck. Any other earned strain fighting arts should be stored in your game box for later campaigns.