You sacrifice attacks to parry blows.

Prerequisite(s): Three or more arms, Dex 21

Benefit: When you make a full-attack action, you may choose not to take an attack with a number of your wielded weapons other than your primary weapon. For each attack you forgo, you gain a +1 shield bonus to your AC for that round. This bonus stacks with itself to a maximum bonus of +5, but not with shield bonuses to AC from other sources.