Bāṇāsura was a descendent of Mahā Bali from whom Lord Vāmana Mūrti managed to get the entire land, as gift. The furious battle waged by Lord Kṛṣṇa against Bāṇāsura and how, in the end, he was let off with a bare four arms, out of the thousand he had, at the special intervention and request of Rudra, have been set out already, in great detail, in the notes below III-10-4.