"Ba" is her proper name, with the nü being an added indication of being feminine and han meaning "drought".
Ba is the daughter of the Yellow Emperor (Huangdi) whom she aided during his Battle at Zhuolu against Chiyou.
After Chiyou had fielded a wind god (Feng Bo) and a rain god (Yu Shi), Ba descended from heaven to use her drought power to defeat their wind and rain powers.
She is one of the first goddesses attested to in Chinese literature, appearing in the early collection of poetry, the Shijing, as well as in the later Shanhaijing.
[4][5] Up through the middle of the twentieth century, ceremonies to produce rain were held in many regions of China.