Palace Maid

The Maid was one of the revolutionaries who was tasked with assisting Tatsumi and Lubbock with infiltrate the royal palace.

History
The maid was tasked to randevu with Tatsumi and Lubbock in order to assist them in infiltrating the royal palace. Sneaking past the courtyard, they head to the group's hideout, only to find out their allies were killed and their bodies rigged with bombs.

Barely evading the massive explosion, they're quickly ambushed by Syura and Budo. In the midst of the battle, the woman grabs hold of Lubbock in order to assist Syura, while apologizing at the same time for her betrayal. Angered by her interference, Syura cuts the Maid's neck, labeling her as nothing more than a toy. With his attention diverted, Lubbock manages to trap Syura within the reach of his threads, but before he can get a chance to question him, the woman picks up Syura's knife and stabs Lubbock in the back with it. As she succumbs to her previously inflicted wound, the maid asks of Syura to remember this as a token of her service to him and asks of Syura to release her parents from his custody. Syura responds to her request with a maniacal laughter, noting that he had already killed them.

Trivia

 * She was never given an official name, but rather referred to as a "Maid" on anime's official website.