Kaikasi was the beautiful daughter of Sumali, who was a Rakshasa chieftain. Her father asked her to take Sage Vishravas as her husband so that she can have strong and powerful children.
Sumali and other rakshasas were thrown out of Lanka and they returned only after they agreed to accept Kubera as the king of Lanka. Kubera was the son of Sage Vishravas.
Kaikasi obeyed her father’s orders and reached to the ashram of Sage Vishravas on an evening. The sage was preparing for evening prayers and yajna. The sage soon realized that she has arrived with the intention of getting married him.
He asked Kaikasi to wait for an opportune time, as lovemaking in the evening will produce violent offspring. However, Kaikasi was adamant.
The sage then fulfilled her desire. She then stayed with the Sage Vishravas.
Kaikasi then gave birth to Ravana, Kumbhakarna and Vibhishana.