The Ascension Project
Advanced Two-Weapon Fighting
Prerequisites: Dexterity 13, Two-Weapon Fighting, Improved Two-Weapon Fighting, base attack bonus +11.
Benefit: The character’s penalties for fighting with two weapons are lessened by an additional 2 for the primary hand and the off hand (for a total of 6). The character also gets a single extra attack with one of their weapons, albeit at a –10 penalty.