Agastyar — Tamil Siddhar

Agastyar, known in Sanskrit as Agastya, is revered simultaneously as a Vedic rishi, the father of Tamil grammar, and the foremost of the eighteen Siddhars. He is credited with composing hymns of the Rigveda, subduing the Vindhya mountains when they grew arrogant and blocked the sun's path, and drinking the entire ocean in a single gulp to expose the Kalakeya demons hiding beneath its waters. In Tamil tradition, Shiva himself is said to have commanded Agastyar to travel south to balance the earth's weight during the celestial wedding of Shiva and Parvati at Mount Kailash, since the northern regions had become overcrowded with celestial beings. Settling in the Podhigai hills of the Western Ghats, he composed the first Tamil grammar, the Agattiyam, and is honored as the patriarch of the Tamil Sangams. As a siddhar, he is believed to have achieved kaya siddhi, a deathless body sustained through alchemical and yogic means, and continues to dwell invisibly in the Agastya Malai, appearing to worthy disciples across centuries. His teachings blend Vedic ritualism, Tamil linguistics, yogic practice, and an encyclopedic knowledge of alchemy and herbal medicine, making him the archetype of the polymath sage whose wisdom spans both northern and southern Indian traditions.

Agastyar is regarded as one of the principal architects of Siddha medicine, credited with over three hundred treatises covering kaya kalpa rejuvenation, toxicology, gynecology, and the alchemical processing of mercury, sulphur, and mica into medicinal parpams and chendurams. His texts, collectively called the Agastyar Nool corpus, describe muppu, the mystical universal salt used as a catalyst in transmuting metals and preparing life-extending medicines. He is said to have personally treated diseases through pulse diagnosis (nadi pariksha) and to have taught disciples like Bogar and Konganar the deeper alchemical secrets of rasavadam, positioning him as the primary transmitter of siddha pharmacology to the later lineage of Tamil alchemist-physicians.