The naga are divine, semi-divine deities or a semi-divine race of half-human half-serpent beings that reside in the underworld (Patala) and can occasionally take human form. They are principally depicted in three forms: wholly human 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," and are said to be both beautiful and clever. Nagaraja is seen as the king of nagas. They are common and hold cultural significance in the mythological traditions of many South Asian and Southeast Asian cultures.
The nagas possess many of the world's finest jewels, which they use to illuminate the underground palaces in which they dwell. Because of their defensive powers, statues of nagas are often placed at the entrances of temples. In some depictions, they live in the bottoms of lakes and seas and enjoy singing and dancing when they are not fighting.
In Buddhism and Jainism, a naga is a half-snake and half-human hybrid that resides in tribes. They are said to be the enemies of Garuda. They are also said to be the followers of Koumokuten, one of the Four Heavenly Kings. In Hinduism, they are usually depicted as human from the waist up and snake from the waist down. They are regarded as gods of the harvest, fertility and reincarnation. Their venom can kill with one strike, and their bodies are immortal and can heal from any wound.
After defeating the Basilisk, the protagonist can teleport to an isle in the Expanse. On said isle, a Naga is impaled by the Kuchinawa Sword. The protagonist then helps him by using Amitabha's Might to extract the sword. The Naga joins the heroes and gives the blade to them.
"Snake gods of Indian mythology. They are usually depicted as human from the waist up and snake from the waist down. They are regarded as gods of the harvest, fertility, and reincarnation. Their venom can kill with one strike, and their bodies are immortal and can heal from any wound. Female Nagas are called nagini and are said to be both beautiful and clever. The Nagas possess many of the world's finest jewels, which they use to illuminate the underground palaces in which they dwell. Because of their awesome defensive powers, statues of Nagas are often placed at the entrances of temples."
—Shin Megami Tensei IMAGINE compendium
Naga can be contracted within Shinjuku Babel's docks area. A particular floor in the Denshi Kairo instance has a constant respawn of Naga that can only be passed by summoning a Garuda.
"Half-snake, half-human, they are divine beings in Hindu lore. Worshipped as bringers of fertility. They live in the bottoms of lakes and seas, and enjoy singing and dancing when they are not fighting."
Two Naga appear in a mini-boss battle once Flynn enters the 3rd stratum of Naraku. A hooded figure will summon them in an attempt to teach Flynn that there are limits a casualry can't overcome by exerting themselves.
Naga can be found in the Toyosu Shelter and in the Konganji Passage in Ginza. He can teach Nanashi the Head Crush, Bufula, Tarukaja and Fatal Sword skills with his Demon Whisper. Naga benefits from learning Physical and Ice skills.
Upon entering the power plant, the party will come across a couple of Karma Soldiers smashing the consoles which open the main doors allowing access to the deeper parts of the facility. They will transform into Naga to engage the party. They will also be encountered in random battles in the area. In the boss battle against Raja Naga, he will summon reinforcement of Nagas infinitely to ensure there are always 2 Nagas fighting alongside him.
"Snake gods of Indian mythology, depicted as being half-snake and half-human. They are regarded as gods of rebirth or reincarnation. The Naga live at the bottom of lakes, in rivers and oceans. When they are not at war, they live a joyful life singing and dancing."