Taken from BGwiki:
*Dual Wield +5%.
*'Augments Innin' is thought to grant additional Double Attacks from the back.
*Upgraded from Iga Zukin +1 via Magian Trial 4228.
Unfortunately nobody is aware of/published the statistics of "Augments Innin", "Enhances dual wield" and "Augments dual wield".
Again, Haste and Dual wield cap independently of one another meaning Ninja are going to get a serious attack speed boost. Further contributing to my presumption that us Ninja are going to become DD/DoT.
A STRAIGHT Dexterity+10 is wow. Critical hit rate boost AND major Katana weaponskill modifier. Also in the case of Blade: Jin they are both serious ws modifiers.
The only major thing this set (as of the 85 update) is lacking is ninjutsu bonuses, whether damage%+/skill/accuracy. I expect these stats will be added with the next update where presumably the body and hands of the Empyrian sets will be added.