The guardian applies a buff to the party granting +5-15 Armor for 10–30 seconds, depending on the caster's Constitution. However, the armor provided by this buff decays over time; the amount of armor granted is equal to 2.5 armor per 5 seconds remaining (rounded up).
This ability will stack with itself, but existing stacks retain their duration.
Duration is equal to 5*(1 + ceil(0.05*[Con-10])), limited to the range [10, 30]. With Master Guardian it is instead 5*(1 + ceil(0.15*[Con-10])).