In Hinduism, Buddhism and Jainism, the nāga (IAST: nāga; Devanāgarī: नाग) or Nagi (f. of nāga; IAST: nāgī; Devanāgarī: नागी) are divine, semi-divine deities, or a semi-divine race of half-human half-serpent beings that reside in the netherworld (Patala) and can occasionally take human form. They are principally depicted in three forms: wholly humans with snakes on the heads and necks; common serpents or as half-human half-snake beings. A female naga is a "nagi", "nagin", or "nagini". Nagaraja is seen as the king of nāgas and nāginis. They are common and hold cultural significance in the mythological traditions of many South Asian and Southeast Asian cultures.
In Sanskrit, a nāgá (नाग) is a cobra, the Indian cobra (Naja naja). A synonym for nāgá is phaṇin (फणिन्). There are several words for "snake" in general, and one of the very commonly used ones is sarpá (सर्प). Sometimes the word nāgá is also used generically to mean "snake". The word is cognate with English 'snake', Germanic: *snēk-a-, Proto-IE: *(s)nēg-o- (with s-mobile).
The mythological serpent race that took form as cobras often can be found in Hindu iconography. The nāgas are described as the powerful, splendid, wonderful and proud semidivine race that can assume their physical form either as human, partial human-serpent or the whole serpent. Their domain is in the enchanted underworld, the underground realm filled with gems, gold and other earthly treasures called Naga-loka or Patala-loka. They are also often associated with bodies of waters — including rivers, lakes, seas, and wells — and are guardians of treasure. Their power and venom made them potentially dangerous to humans. However, they often took beneficial protagonist role in Hindu mythology, such as in Samudra manthan mythology, Vasuki, a nāgarāja who abides on Shiva's neck, became the churning rope for churning of the Ocean of Milk. Their eternal mortal enemies are the Garudas, the legendary semidivine birdlike-deity.
Vishnu is originally portrayed in the form sheltered by Śeṣanāga or reclining on Śeṣa, but the iconography has been extended to other deities as well. The serpent is a common feature in Ganesha iconography and appears in many forms: around the neck, use as a sacred thread (Sanskrit: yajñyopavīta) wrapped around the stomach as a belt, held in a hand, coiled at the ankles, or as a throne. Shiva is often shown garlanded with a snake. Maehle (2006: p. 297) states that "Patanjali is thought to be a manifestation of the serpent of eternity".
As in Hinduism, the Buddhist nāga generally has the form of a great cobra, usually with a single head but sometimes with many. At least some of the nāgas are capable of using magic powers to transform themselves into a human semblance. The nāga is sometimes portrayed as a human being with a snake or dragon extending over his head. One nāga, in human form, attempted to become a monk; and when telling it that such ordination was impossible, the Buddha told it how to ensure that it would be reborn a human, and so able to become a monk.
In the "Devadatta" chapter of the Lotus Sutra, the daughter of the dragon king, an eight year old longnü (nāga), after listening to Mañjuśrī preach the Lotus Sutra, transforms into a male Bodhisattva and immediately reaches full enlightenment. This tale appears to reinforce the viewpoint prevalent in Mahayana scriptures that a male body is required for Buddhahood, even if a being is so advanced in realization that they can magically transform their body at will and demonstrate the emptiness of the physical form itself.
Nagas are believed to both live on Nagaloka, among the other minor deities, and in various parts of the human-inhabited earth. Some of them are water-dwellers, living in streams or the ocean; others are earth-dwellers, living in underground caverns.
The nāgas are the followers of Virūpākṣa (Pāli: Virūpakkha), one of the Four Heavenly Kings who guards the western direction. They act as a guard upon Mount Sumeru, protecting the dēvas of Trāyastriṃśa from attack by the asūras.
Among the notable nāgas of Buddhist tradition is Mucalinda, Nāgarāja and protector of the Buddha. In the Vinaya Sutra (I, 3), shortly after his enlightenment, the Buddha is meditating in a forest when a great storm arises, but graciously, King Mucalinda gives shelter to the Buddha from the storm by covering the Buddha's head with his seven snake heads. Then the king takes the form of a young Brahmin and renders the Buddha homage.
It is noteworthy that the two chief disciples of the Buddha, Sariputta and Moggallāna are both referred to as Mahānāga or "Great Nāga". Some of the most important figures in Buddhist history symbolize nagas in their names such as Dignāga, Nāgāsēna, and, although other etymons are assigned to his name, Nāgārjuna.
The seven-headed nagas often depicted as guardian statues, carved as balustrades on causeways leading to main Cambodian temples, such as those found in Angkor Wat. Apparently they represent the seven races within naga society, which has a mythological, or symbolic, association with "the seven colors of the rainbow". Furthermore, Cambodian naga possess numerological symbolism in the number of their heads. Odd-headed naga symbolise the Male Energy, Infinity, Timelessness, and Immortality. This is because, numerologically, all odd numbers come from One (1). Even-headed naga are said to be "Female, representing Physicality, Mortality, Temporality, and the Earth."
In Javanese and Balinese culture, Indonesia, a naga is depicted as a crowned, giant, magical serpent, sometimes winged. It is similarly derived from the Shiva-Hinduism tradition, merged with Javanese animism. Naga in Indonesia mainly derived and influenced by Indic tradition, combined with the native animism tradition of sacred serpents. In Sanskrit the term naga literally means snake, but in Java it normally refer to serpent deity, associated with water and fertility. In Borobudur, the nagas are depicted in their human form, but elsewhere they are depicted in animal shape.
Early depictions of circa-9th-century Central Java closely resembled Indic Naga which was based on cobra imagery. During this period, naga serpents were depicted as giant cobras supporting the waterspout of yoni-lingam. The examples of naga sculpture can be found in several Javanese candis, including Prambanan, Sambisari, Ijo, and Jawi. In East Java, the Penataran temple complex contain a Candi Naga, an unusual naga temple with its Hindu-Javanese caryatids holding corpulent nagas aloft.
The later depiction since the 15th century, however, was slightly influenced by Chinese dragon imagery—although unlike its Chinese counterparts, Javanese and Balinese nagas do not have legs. Naga as the lesser deity of earth and water is prevalent in the Hindu period of Indonesia, before the introduction of Islam.
In Balinese tradition, nagas are often depicted battling Garuda. Intricately carved naga are found as stairs railings in bridges or stairs, such as those found in Balinese temples, Ubud monkey forest, and Taman Sari in Yogyakarta.
Naga are believed to live in the Laotian stretch of the Mekong or its estuaries. Lao mythology maintains that the naga are the protectors of Vientiane, and by extension, the Lao state. The naga association was most clearly articulated during and immediately after the reign of Anouvong. An important poem from this period San Leupphasun (Lao: ສານລຶພສູນ) discusses relations between Laos and Thailand in a veiled manner, using the naga and the garuda to represent the Lao and the Thai, respectively. The naga is incorporated extensively into Lao iconography, and features prominently in Lao culture throughout the length of the country, not only in Vientiane.
In Thailand and Laos, Phaya Naga are nāga believed by locals to live in the Mekong river or estuaries.
In Malay and Orang Asli traditions, the lake Chini, located in Pahang is home to a naga called Sri Gumum. Depending on legend versions, her predecessor Sri Pahang or her son left the lake and later fought a naga called Sri Kemboja. Kemboja is the Malay name for Cambodia. Like the naga legends there, there are stories about an ancient empire in lake Chini, although the stories are not linked to the naga legends.
The Nāga where often called Bakunawa, a serpent-like dragon in Philippine mythology. It is believed to be the cause of eclipses, earthquakes, rains, and wind. The movements of the bakunawa served as a geomantic calendar system for ancient Filipinos and were part of the shamanistic rituals of the babaylan. It is usually depicted with a characteristically looped tail and was variously believed to inhabit either the sea, the sky, or the underworld. The common assumption is that the belief in Bakunawa is an indigenous legend, and has been a part of ancient astronomy and rituals in the Philippines since people first arrived to the region. In reality, stories of Bakunawa are directly linked to the Hindu demi-god “Rahu”, from India’s Vedic period ( c. 1500 – c. 500 BCE) and was brought to SE Asia through trade and the expansion of the Indianized Kingdoms around 200BCE. The stories travelled to areas of the Philippines through trade and subsequent migrations between 200-900CE. Evidence of Rahu being brought to SE Asia also exists in Javanese Mythology, Thai Mythology, and other Hindu influenced areas such as China.