Rati is desire as a goddess, the wife of Kamadeva, the god of love, and the pleasure that answers to his longing; her name is the ordinary Sanskrit word for erotic delight. Her role turns the central Kama myth on its hinge: when the gods send Kama to break Shiva's meditation and Shiva opens his third eye and burns him to ash, it is Rati's grief, her mourning and her plea, that wins the concession by which Kama is allowed to live on, though bodiless, which is why desire is everywhere and yet cannot be seen.
In the Puranic sequel both are reborn: Kama as Pradyumna, the son of Krishna, and Rati as Mayavati, who raises the child (not knowing who he is) and later becomes his wife. She is a daughter of Daksha in most accounts. She is rarely worshipped alone, appearing beside Kama at the spring festivals, but she carries a claim the tradition does not disown: that desire has a consort and is not, in itself, a thing to be ashamed of.