Shield of Righteousness is resolved as a melee special attack. It can miss, be dodged, be parried, be blocked, and critically strike for double damage, with the same chance for each as any other melee attack.
Patch 3.2.0 (2009-08-04): Now deals 100% of shield block value as damage instead of 130%. In addition, the benefit from additional block value this ability gains is now subject to diminishing returns. Diminishing returns occur once block value exceeds 30 times the player's level and caps the maximum damage benefit from shield block value at 34.5 times the player's level.
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Patch 3.2.0 (2009-08-04): Now deals 100% of shield block value as damage instead of 130%. In addition, the benefit from additional block value this ability gains is now subject to diminishing returns. Diminishing returns occur once block value exceeds 30 times the player's level and caps the maximum damage benefit from shield block value at 34.5 times the player's level. 
