The illustrious Shukra had four sons who were also the preceptors of the Asuras. Their names were Tvashtadhara and Atri and two others of fearful deeds.
ख्याताश्चोशनसः पुत्राश्चत्वारोऽसुरयाजकाः। त्वष्टाधरस्तथात्रिश्च द्वावन्यौ रौद्रकर्मिणौ॥