Shirogane Saiga, real name Éléonore (エレオノール), is a young French woman who came to Japan to protect Masaru Saiga and repay the debt she feels from Masaru's grandfather, Shoji Saiga, for helping her family. In fact, her relationship with Masaru's "family" is more complex than that.

Shirogane was raised as an orphan in Quiberon, France, where she was callously taught on how to manipulate puppets. She becomes a circus artist, Masaru's bodyguard/caretaker and controls Harlequin, one of the most powerful puppets in the series.

Shirogane is a young pale-skinned lady with neck-length silver hair that has bangs swept to the left side, silver eyes, and a slender body with large breasts.

(Source: Karakuri Circus Wiki, edited)