i like the fruits basket sotory peronaly i dount wana spoil it :)
wah?! Akito's a woman?! So what... why does he... i mean she... treat the zodiac members so meanly? I want a full spoiler!... Is that ok?
Yeah it's fine. Once I'm done with all my translations I finish off the volume summaries so I'll do this quickly.
Basically, Akito has been mentally damaged by Ren. When her father Akira died, she became the head of the house but it also gave Ren freedom to torment Akito. She told her over and over that her bond with the Jyuniishi was false and that no one loved her. When she died she would be alone and unloved.
Of course, saying this to a five year old (about five anyway) really doesn't do much good for their mental health and so Akito became paranoid and feared what her mother said would come true. Later, AKito made a bet with Ren to try and prove her wrong. If she let them leave the estate, and they came back to her it would prove their bond was real. However if they left and didn't return to her Akito had to bow before Ren and leave the Sohma family.
In the end, it became a mixture of fear of losing the bet, and fear of being alone and unloved that made Akito somewhat insane. She would lash out each time she saw they might leave her (eg. Hiro and Kisa, Hatori and Kana, Haru and Rin) in attempt to keep them close to her. When Kureno was freed when she was young it only made her more fearful that the bond wasn't real and so she kept him as lcose as she could, fearing he would be the first to leave as he was no longer cursed. It seems she feels most vulnerable when she see's them together, with a lover, so lashes out most then. (Perhaps feeling they're replacing her with their lover.)