Īśvara (Iswara) is one of the grandsons of Brahmā (Brahma) and one of the eleven Rudras who were the partial incarnations of Sthāṇu (Sthanu) or Mahādeva (Mahadeva).
Īśvara is one of the Rudras who were present during the birth-ceremony of Arjuna, the third Pāṇḍava (Pandava).