In Buddhism, Vairocana is the greatest of the "Dhyanibuddhas," the Five Great Buddhas of Wisdom. He encompasses the principle of "Absolute." In Tibet, he is said to ride a snow leopard as his mount. He is also said to have introduced the Yogacara school of Mahayana Buddhism to humans. He is called Dainichi Nyorai, or Dainichi (大日如来) for short, in Japan. His wrathful emanation is called Acala (or Fudou Myouou).
In Hinduism, Virochana is the name of the king of Asuras who, together with Indra, went to Prajapati for guidance towards enlightenment regarding the self. Virochana is also the name of a solar deity mentioned in the Mahabharata, though this deity is separate from the Asura Virochana. It is unknown if either of them went on to inspire the Buddhist Vairocana.
An additional demon exclusive to the PC-Engine release, Dainichi Nyorai can be created by fusing Crusader, Missionary and Amaterasu. Upon being fused, he identifies himself as a Tenma, but his status screen identifies him as a Tyrant. He is also the only Tyrant not aligned with Chaos (instead being aligned with Neutral).
Devil Summoner 2: Raidou Kuzunoha vs King Abaddon
Wishing to be restored to his original form of Ahura Mazda, Dainichi Nyorai, in the form of Asura, uses his power over time and space to travel through the Akarana Corridor to an alternate space time where the forces of Chaos do battle with the forces of Law in order to lead them against the Law faction. After Asura is defeated by Raidou Kuzunoha the XIV, he must choose whether to let him fight in that alternate world as Asura or return to his duties as Dainichi Nyorai.
In Tatsuya's Scenario, Virocana resides in the Tower of Reason in Kadath Mandala. He questions what the true essence of the self is, atman? Is there or is there not an "I" on the inside. Maya's answer of saying there is an "I" angers Virocana, who wishes for the woman of Illusions who unmasks the truth to disappear from his sight.
After visiting the Tadashi Satomi drugstore inside Kadath Mandala, Virocana reappears. Proclaiming that the self reflected in the water is the true self atman and the truth of the universe, Brahman. As ones pursuing the truth, he grants them wisdom and the Trapezohedron of Reason.