Hitagi Senjougahara

Gahara-san, Senshougahara-san, Tsundere-chan, 戦場ヶ原ひたぎ

Hitagi is the main female character in Bakemonogatari. Despite appearing weak, she suffers from an uncurable disease that makes her nearly weightless. Although they are classmates, Koyomi rarely interacts with her due to her aloof nature. In her first year of high school, Hitagi encountered a mysterious crab and became almost weightless. Since then, she has kept herself isolated and threatened anyone who discovers her secret. She humorously identifies as a tsundere and uses sharp language in her speech.

Spoilers:

She also seems to have a father complex as she becomes excited to the point of being unable to fall asleep when using her fathers blanket. She also seems to have a father complex as she becomes excited to the point of being unable to fall asleep when using her father's blanket. (5 kg when she was under the influence of the heavy crab) At the end of Mayoi Snail, she admits that she loves Koyomi, and subsequently enters into a relationship with him.After the events in Tsukihi Phoenix, she overcomes her trauma and becomes a rather cheerful and normal girl. She starts calling Araragi with a cute nickname, chuckling at small things, and sending e-mails full of emoticons. Her sharp tongue is still present albeit toned down.