1. Varuṇa

Varuṇa (Sanskrit: वरुण) is a Vedic deity associated initially with the sky, later also with the seas as well as Ṛta (justice) and Satya (truth).

He is found in the oldest layer of Vedic literature of Hinduism, such as hymn 7.86 of the Ṛg Veda. He is also mentioned in the Tamil grammar work Tolkāppiyam, as the god of sea and rain.

He is said to be the son of Kaśyapa (one of the 7 ancient sages).

In the Hindu Purāṇas, Varuṇa is the god of oceans, his vehicle is a Makara (part fish, part land creature) and his weapon is a Pāśa (noose, rope loop).

He is the guardian deity of the Western direction.
In some texts, he is the father of the Vedic sage Vāsiṣṭha.

Varuṇa is found in Japanese Buddhist mythology. He is also found in Jainism.

2. Etymology

The name Varuṇa is a derivation from the verbal vṛ ("to surround, to cover" or "to restrain, bind") by means of an ending -uṇa-, for an interpretation of the name as "he who covers or binds", in reference to the cosmological ocean or river encircling the world, but also in reference to the "binding" by universal law or Ṛta.

3. Vedas

In the earliest layer of the Ṛg Veda, Varuṇa is the Guardian of Moral Law, one who punishes those who sin without remorse, and who forgives those who err with remorse.

He is mentioned in many Ṛg Vedic hymns, such as 7.86–88, 1.25, 2.27–30, 8.8, 9.73 and others.

His relationship with waters, rivers and oceans is mentioned in the Vedas.

Vedic poets describe him as an aspect and one of the plural perspectives of the Agṇi, one of the Primary deities For example, hymn 5.3 of the Ṛg Veda states:

You at your birth are Varuṇa, O Agṇi.
When you are kindled, you are Mitra.
In you, O son of strength, all gods are centred.
You are Indra to the mortal who brings oblation.
You are Āryaman, when you are regarded as having
 the mysterious names of maidens, O Self-sustainer.

— Ṛg Veda 5.3.1-2

Varuṇa and Mitra are the gods of the societal affairs including the oath, and are often twinned Mitra-Varuṇa.

Both Mitra and Varuṇa are classified as Asuras in the Ṛg Veda (e.g. RV 5.63.3), although they are also addressed as Devas as well (e.g. RV 7.60.12).

Varuṇa, being the King of the Asuras, was adopted or made the change to a Deva after the structuring of the primordial cosmos, imposed by Indra after he defeats Vṛtra.

According to some Indologists, Varuṇa-Mitra pair is an ambiguous deity just like Rudra-Shiva pair. Both have wrathful-gracious aspects in Indian mythology:

Both Varuṇa and Rudra are synonymous with "all comprehensive sight, knowledge", both were the guardian deity of the North in the Vedic texts (Varuṇa later gets associated with West), both can be offered "injured, ill offerings", all of which suggest that Varuṇa may have been conceptually overlapping with Rudra.

Further, the Ṛg Vedic hymn 5.70 calls Mitra-Varuṇa pair a Rudra.

According to some scholars, Varuṇa had been the more ancient Indo-Aryan deity in 2nd millennium BCE, who gave way to Rudra in the Hindu pantheon, and Rudra-Śiva became both "timeless and the god of time".

In Vājasaneyī Saṁhitā 21.40 (Yajurveda), Varuṇa is called the patron deity of physicians, one who has "a hundred, a thousand remedies".

His capacity and association with "all comprehensive knowledge" is also found in the Atharvaveda (~1000 BCE).

Varuṇa also finds a mention in the early Upanishads, where his role evolves:

In verse 3.9.26 of the Brihadāraṇyaka Upanishad (~800 BCE), for example, he is stated to be the God of the Western quarter, but one who is founded on "water" and dependent ultimately on "the heart" and the fire of soul.

In the Kaṭha Upanishad, Aditi is identified to be same as the Goddess Earth:

She is stated in the Vedic texts to be the Mother of Varuṇa and Mitra along with other Vedic gods, and in later Hindu mythology she as Mother Earth is stated to be Mother of all Gods.

In Yajurveda it is said:

"In fact Varuṇa is Viṣṇu and Viṣṇu is Varuṇa
and hence the auspicious offering is to be made to these deities." || 8.59 ||

4. Rāmāyaṇa

Rāma interacts with Varuṇa in the Hindu epic Rāmāyaṇa:

For example, faced with the dilemma of how to cross the Ocean to Lanka, where his abducted wife Sītā is held captive by the demon king Rāvaṇa, Rāma (an Avatar of Viṣṇu) performs a prayer (tapasya) to Varuṇa, the Lord of Oceans, for 3 days and 3 nights.

Varuṇa does not respond, and Rāma arises on the fourth morning, enraged:

He states to his brother Lakṣmaṇa that "even lords of the elements listen only to violence, Varuṇa does not respect gentleness, and peaceful prayers go unheard".

With his bow and arrow, Rāma prepares to attack the oceans to burn up the waters and create a bed of sand for his army of monkeys to cross and thus confront Rāvaṇa.

Lakṣmaṇa appeals to Rāma that he should return to "peaceful paths of our fathers, you can win this war without laying waste the sea".

Rāma shoots his weapon sending the ocean into flames.

As Rāma increases the ferocity of his weapons, Varuṇa arises out of the oceans:

He bows to Rāma, stating that he himself did not know how to help Rāma because the sea is deep, vast and he cannot change the nature of sea.

Varuṇa asked Rāma to remember that he is "the soul of peace and love, wrath does not suit him". Varuṇa promised to Rāma that he will not disturb him or his army as they build a bridge and cross over to Lanka.

5. In Tolkāppiyam

The Tolkāppiyam, a Tamil grammar work from 3rd century BCE divides the people of ancient Tamilakam into 5 Sangam landscape divisions: kurinji, mullai, paalai, marutham and neithal.

Each landscape is designated with different Gods:

Neithal is described as a seashore landscape occupied by fishermen and sea-traders, with the God of sea and rain, Varuṇan or Kadalon.

"Varuṇa" means water which denotes the ocean in the Tamil language.

6. Sindhi Hindus

Jhulelal is believed by Sindhi Hindus to be an incarnation of Varuṇa. They celebrate the festival of Chetrī Chand in his honour. The festival marks the arrival of Spring and harvest,

but in Sindhi community it also marks the mythical birth of Uderolal in year 1007, after they prayed to Hindu god Varuṇa to save them from the persecution by tyrannical Muslim ruler named Mirkhshah.

Uderolal morphed into a warrior and old man who preached and reprimanded Mirkhshah that Muslims and Hindus deserve the same religious freedoms.

He, as Jhulelal, became the champion of the people in Sindh, from both religions.

Among his Sufi Muslim followers, Jhulelal is known as "Khwāja Khizir" or "Sheikh Tahit". The Hindu Sindhi, according to this legend, celebrate the New Year as Uderolal's Birthday.

7. Theravada Buddhism

The Pāli Canon of the Theravada school recognizes Varuṇa as a king of the Devas and companion of Sakka, Prajāpati and Īśāna. In the battle against the Asuras, the Devas of Tāvatiṁsa were asked to look upon the banner of Varuṇa in order to have all their fears dispelled.

The Tevijja Sutta mentions him among Indra, Soma, Īśāna, Prajāpati, Yama and Mahiddhi as gods that are invoked by the Brahmins.

The Ātānātiya Sutta lists him among the Yakkha chiefs.

Buddhaghosa states that Varuṇa is equal in age and glory with Sakka (Indra) and takes the third seat in the assembly of devas.

8. Mahayana Buddhism

In East Asian Buddhism, Varuṇa is a Dharmapāla (protector of tradition) and often classed as one of the 12 Devas (Japanese: Jūniten). He presides over the Western direction.

In Japan, he is called "Suiten" (lit. "water deva"). He is included with the other 11 devas, which include:

Taishakuten (Śakra/Indra), Fūten (Vāyu), Emmaten (Yama), Rasetsuten (Nirṛtī/Rākṣasa), Ishanaten (Īśāna), Bishamonten (Vaiśravaṇa/Kubera), Katen (Agṇi) Bonten (Brahmā), Jiten (Pṛthvī), Nitten (Sūrya/Āditya), and Gatten (Candra).

9. Shinto

Varuṇa is also worshipped in Japan's Shinto religion. One of the Shinto shrines dedicated to him is the Suitengū ("Palace of Suiten") in Tokyo.

After the Japanese emperor issued the separation of Shinto and Buddhist practices as part of the Meiji Restoration, Varuṇa/Suiten was identified with the Japanese supreme God, Amenominakanushi ("Heavenly Ancestral God of the Originating Heart of the Universe").