Oryou

About

Oryou is the humanoid form of Rider's Noble Phantasm, Like a Soaring Dragon. The black-haired woman who follows by Ryouma’s side, Oryou. Falling in love at first sight with Ryouma when he saved her from her seal on a certain mountain, a fine lady who stalks Ryouma with the excuse of repaying the favor. Strictly speaking, she is not a dragon, but a lesser specter more closely related to snakes and serpents.

(Source: Type-Moon Wiki)