Source: Dragon #346
By warping its truename, you can make your foe easier to harm.
Prerequisite: Truespeak 12 ranks, any recitation feat, ability to speak utterances, must know your own personal truename.
Benefit: You lower a creature's damage reduction by 5 for 3 rounds when you succeed on a Truespeak check to say its personal truename. The Truespeak DC to use this denouncement is 10 higher than normal.
This feat does not grant you knowledge of a creature's damage reduction. It has no effect on creatures immune to a type of damage. The reduction caused by this feat stacks with itself. You may, for example, reduce a creature's damage reduction by 5 one round and an additional 5 the following round. Using the ability in this way does not change the duration, so the first reduction you create ends 1 round before the next. You may also choose to reduce multiple forms of damage reduction from the same creature, with each reduction having its own duration.