Bladesong Symmetry (3.5e Feat)
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Bladesong Symmetry [Bladesinger]
Allows you to use part of your Bladesong AC bonus when two-weapon fighting, with certain conditions.
Benefit: This feat allows you to retain one half of your Bladesong's bonus to armor class (rounded down) while fighting with a weapon in each hand, given that your off-hand weapon is a rapier.
Normal: Two-weapon fighting denies you the bonus AC granted by Bladesong style.
Special: Using this style of fighting is really only useful for the Bladesinger Prestige Class, and doing so denies you your ability to cast spells with somatic components, unless you have the Somatic Weaponry feat or some other means of casting spells with somatic components.