Tannhäuser: Mizu (2011)

Description from the publisher:

Officially an "international liason" for the Shōgunate, Mizu Kage prefers to conduct her diplomacy with Willow and Winding Stream, her deadly sai blades. She has twice saved "the Daimyo" from certain death and three times taken down misguided Reich soldiers who thought to betray their tentative alliance with the Shōgunate. Now charged to collect information that the Shōgunate's Reich allies have been withholding, Mizu works toward the completion of her task like a whisper of wind through the night trees.

With her sai, shuriken, and happo, she can decide to tread a path of blood or conduct an infiltration, unseen and unheard. As a member of the Shōgunate, Mizu may partner with forces from the Reich, according to the Nippon Accords, or she may feature in a team made exclusively from Shōgunate characters.