For each rank of Warding applied to a creature, they gain +5 DR. Each point of damage negated by the Warding condition’s DR removes 1 point of DR from the Warding’s effect for any future damage. The DR from Warding prevents damage before the DR from any other effect.
Ranks of Warding from multiple sources do not stack. If a new application of Warding is granted to a creature, they retain whichever application of Warding grants the most DR, and the other one is lost.
Warding is a stand-in for any kind of ablative protection that a character grants to themselves or someone else. It can take the form of extraordinary health and resilience, magical shields protecting someone, toughened hide, or magical luck that stops a blow from striking as hard as it should.