Overview
Shesha (Sanskrit: शेष, Śeṣa, meaning 'Remainder') is a serpentine demigod (naga) revered in Hinduism as the king of serpents (Nagaraja) and a primordial being associated with creation. He is also known by the epithets Sheshanaga ('the snake Shesha') and Adishesha ('first Shesha'). His name, derived from the Sanskrit root śiṣ, signifies 'he who remains', reflecting the belief that Shesha endures even when the world is dissolved at the close of each kalpa.
In the Puranas, Shesha is described as bearing all the planets of the universe upon his hoods and continuously singing the glories of Vishnu through his many mouths. He is frequently referred to as Ananta ('without end') or Ananta Shesha ('endless remainder'), names that emphasise his association with infinity and continuity. The Narayana form of Vishnu is commonly depicted reclining on Shesha upon the cosmic ocean, accompanied by the goddess Lakshmi. Alongside the eagle Garuda, Shesha is regarded as one of the two mounts of Vishnu.
According to the Adi Parva of the Mahabharata, Shesha was born to the sage Kashyapa and Kadru, the mother of serpents. Other accounts, however, present him as a primordial being brought forth by Vishnu himself. Traditional narratives further hold that Shesha has descended to the earth in human form on more than one occasion. He is identified with Lakshmana, the brother of Rama, the incarnation of Vishnu in the Treta Yuga. According to certain traditions, he also appeared as Balarama, the elder brother of Krishna, Vishnu's incarnation in the Dvapara Yuga.
Shesha thus occupies a distinctive place in Hindu cosmology, functioning simultaneously as a divine attendant of Vishnu, a cosmic support of the universe, and a symbol of that which endures beyond cyclical creation and dissolution.
References
Adapted from the English Wikipedia article on Shes