He had an elder brother named Hiranyakashipu, who after having undertaken penances which made him incredibly powerful and invincible unless several conditions were met, was later slain by Narasimha, another avatar of Vishnu.
Kashyapa (Sanskrit कश्यप kaśyapa) was an ancient sage (rishis), who is one of the Saptarshis in the present Manvantara; with others being Atri, Vashishtha, Vishvamitra, Gautama, Jamadagni, Bharadwaja 
He was the father of the Devas, Asuras, Nagas and all of humanity. He married Aditi, with whom he fathered Agni, the Aditya. With his second wife, Diti, he begot the Daityas. Diti and Aditi were daughters of King Daksha Prajapati and sisters to Sati, Shiva's consort.
Diti conceived a child in the evening time, whom she carried for a hundred years in the womb. She thus gave birth to Hiranyaksha.
- Dictionary of Hindu Lore and Legend (ISBN 0-500-51088-1) by Anna Dhallapiccola