Kitiara is Raistlin and Caramon's older sister. When their mother died, she raised them as her own children. She had always been a great warrior, and made a mercenary career. One day she met Tanis, and both fell in love. But they had to break up, because they were as water and fire; complete opposite.
After five long years where the companions were trying to find traces of the true gods, everybody came back, except Kitiara, which broke Tanis's heart. What he didn't know is that she had joined the evil army of Takhisis, and even, she was a dragon lord (which would be like a general).
At the end of the war of the Lance, she was killed by Dalamar at the High Tower of Sorcery of Palanthas.