Mazu (媽祖) is a Chinese sea goddess. Some say she was a tenth century shaman called Lin Moniang (林默娘) who was deified as the protector of seafarers. Myths and legends ascribe various heroic deeds to her, all to do with the sea.
So popular a goddess is she that Mazu is regarded as the Queen of Heaven (天后, Tianhou), the wife of the Jade Emperor. She is also known as Heavenly Consort (天妃); and Holy Heavenly Mother (天上聖母, Tianhou Shengmu). However, some legends say that she is celibate.
One story tells that the demons Qianliyan and Shunfeng’er competed for Mazu’s hand in marriage, but when she defeated them both in combat, they swore eternal loyalty to her and became her guardians. Thus, you can find their statues or images at Mazu temples.