Ashbound Mark

As a member of the Ashbound sect, you use the power of your dragonmark to rid the world of those who practice arcane magic.
Prerequisites: Ashbound, any true or aberrant dragonmark.
Benefit: Against creatures that can cast arcane spells, the saving throw DC of spells you cast increases by 2. In addition, you gain a +1 bonus on attack rolls against any creature that can cast arcane spells.

Source: Dragonmarked