Monogatari,Hitagi Senjougahara

Hitagi Senjougahara (戦場ヶ原 ひたぎ, Senjōgahara Hitagi) is a third-year student of Naoetsu Private High School. She is considered to be a frail-looking girl with an "incurable disease" and is distant from others.
In an accidental encounter with Koyomi Araragi, her closely kept secret is exposed, and triggers a life-changing experience. In the course of the series she receives the nickname Gahara and uses the alias Senshougahara.
She is the titular protagonist of three main arcs: Hitagi Crab, Hitagi End, and Hitagi Rendezvous, and of six minor arcs: Hitagi Buffet, Hitagi Neck, Hitagi Salamander, Hitagi Coin, Hitagi Figure, and Hitagi Throwing