There were in the days of yore two brothers, celebrated throughout the three words by the names of Sunda and Upasunda; they were incapable if being killed by any one else except one by the other.
सुन्दोपसुन्दौ हि पुरा भ्रातरौ सहितावुभौ। आस्तामवध्यावन्येषां त्रिषु लोकेषु विश्रुतौ॥