Ayya Vaikundar, also known as Vaikunda Swami, is believed to be the first and foremost Purna avatar of Eka-Paran, born to Lord Narayana and Goddess Lakshmi at the Sea of Tiruchendur on March 1, 1833 CE. Lord Narayana assumed his ninth incarnation at Tiruchendur, just before the birth of Ayya Vaikundar, and it was this Avatar who gave birth to him as part of the grand and systematic framework for the destruction of Kali.

Goddess Lakshmi was sent to the Sea of Tiruchendur to grow as a giant golden fish called Makara before the birth of Ayya Vaikundar, and he was born from her womb with the Vinchai granted to him immediately after his birth. Ayya Vaikundar's mission was to prepare the world for the Dharma Yukam while Lord Narayana's role was to annihilate Kali, the foremost evil of the 7 yugas. Ayya Vaikundar acted as the subtle medium on whom Lord Narayana had based his platform in the Kaliyuga to destroy Kali.

Since Ayya Vaikundar was born after the severe Tapas of Trimurthi and all other lesser Devas, including the 33 clans of devas and 44 clans of deva-rishis of Seven Logas, he is considered to be the supreme God on his own. He is the central character of Kaliyuga as depicted in the narratives and teachings of Akilathirattu Ammanai. Ayya Vaikundar is an actual historical figure, and his life, teachings, and activities have been documented historically and detailed in critical contemporary sources.

Ayya Vaikundar was a 19th-century Indian spiritual leader and the founder of the Ayyavazhi religion. He was born in 1809 as Mudisoodum Perumal, but according to Ayyavazhi mythology, his soul was replaced by that of the deva Sampooranathevan. Ayya Vaikundar had a special interest in the worship of the Hindu god Vishnu (Narayana), and he earned his living as a Palmyra palm climber and agricultural laborer.

At the age of 24, Ayya Vaikundar disappeared into the sea during a severe illness and emerged three days later as Ayya Vaikundar, declaring that he was the son of Narayana and not of his mother Veyilal Amma. He then started walking towards Detchanam, and upon reaching Poovantanthoppu, he undertook a six-year penance in three stages.

Ayya Vaikundar's teachings were compiled in the Books of Pathiram, Sivakanta Athikara Pathiram, and Thingal Patham, and they emphasized devotion to Narayana and the pursuit of moral and ethical principles. His oral teachings also formed the basis of Ayyavazhi belief, which emphasizes the oneness of all living beings and the rejection of caste-based discrimination. Ayyavazhi also rejects the notion of an organized religion or belief system. Ayya Vaikundar is celebrated as the incarnational date of Ayya Vaikunda Avataram on the 20th of Masi as per the Tamil calendar.