She is from the Hidden Leaf village but she was thrown out due to her clans' blood line trait. She was the last of her clan, or at least in leaf village, the night the nine tailed fox attacked the Hidden Leaf. Instead of killing her, they threw her out of the village at the age of 7 to fend for herself, though she had nothing to do with the attack. She had a crush on Iruka who nearly killed her believing she was the reason why his parents were killed.
Years later when Tsunade became Hokage, She managed to find Karou and bring her back to the village. By that time, they realized she was completely innocent. She still has whisker shaped scars from where Iruka had attacked her on that cursed day.