Sage Agathiyar or Agasthya is the Guru of all Siddhars. He is revered as the Siddha for all the Siddhars. He is one among the divine Saptharishis. Kumba Muni, Thamizh Muni are his other names. Agathiyar Venba, Agathiyar Vaidhya Rathnakaram, are some of the books he has written. His Samadhi is located in Thiruvananthapuram.

As Thirumoolar was passing near Chidambaram he observed an Idaiya man die as he was herding his cattle. Thirumoolar’s soul entered into his body, drove the cattle to their shelter and began his penance in a state of Yogasamadhi at the abode of Koothaperumal. He woke from his penance once every year and sang one verse of Thirumandhiram every year. Thirumoolar’s Thirumandhiram is a 3000 verse book. His Samadhi is in Chidambaram.

Bogar, the Siddhar, carries the glory of creating the main idol of Pazhani Malai Thandayudhapani Swamy in Navapashanam, an intriguing integration of 9 deadly poisons. He is said to have his origin in China. Bogar Nigandu, Bogar 7000, Bogar Karpam, Bogar Vasiyogam are some of his creations. His Samadhi is in Palani hills.

Pulippaani is said to be one of the disciples of Bogar who had assisted him in creating the Navapashanam idol of Pazhani Dhandayudhapani. Legend has it that Pulippaani sat on his tiger, drove it to the forest and fetched the Napashanam herbs to make the famed idol. His Samadhi is said to be in either Ilampillai in Salem district or in Thirupparangundram.

There is a legend that says that Brahma, the four-headed God, got himself created with the order and blessings of Lord Shiva and then began all his Siddha works only to teach everyone. Kamalamuni Pathu, a book is one of his creations. Kamalamuni’s samadhi is located in Thiruvarur.

Sattaimuni is thought to be born to Sinhala parents. Sattaimuni Nigandu, Sattaimuni Moola Sooththiram, Sattaimuni Vaakkiyam are some of his literary creations. His Samadhi is in Seerkazhi near Mayiladuthurai.

Karuvooraar, the Siddhar, is the disciple of Bogar. He is one of the co-creators of Thiruvisappaa. The incidence of Nelaiyappar and his consort Gandhimathi Ammaiyaar showing their dancing position to Karuvooraar is being celebrated as “Avani Moola Thiruvizha” till date. Karuvooraar Pala Thirattu, Karuvooraar Vaadha Kaaviyam, Karuvooraar Pooja Vidhi are some of the books he has created. His Samadhi is in Karuvoor, the present day Karur.

Sundharaanandha Siddha is thought to have originated in Vellala clan. Adhisaya Soothiram, Gnana Soothiram are some of his creations. His Samadhi is said to be in Madurai.

Theraiyar is known as the disciple of Sage Pulathiyar and Sage Dharmasowmiyar. Most ancient Siddha Medicine books also quote that Theraiyar was also a disciple of Sage Agathiyar who also happens to be the Guru of Sage Pulathiyar. His Samadhi is located in Thoranamalai.

Kaalaanginathar is said to one of the main disciples of Thirumoolar. Kaalangi Vaidhya Kaaviyam, Kaalangi Gnaanam are some of his creations. It is said that he traveled to China with the help of a herbal preparation called Gagana Kuligai. His Samadhi is in Kanchipuram.

Paambaatti Siddhar is said to have possessed the eight great Siddhis. He is said to have been an ardent devotee of Lord Shiva who had a passion for Gnana Margam. He is also called a Naagamuni. Since he visualizes the dance of Koothaperuman by the power of his meditation, he has composed his verses with the phrase “Aadu Paambe”. His Samadhi is in Sankarankoil.

Ramadevar, one of eighteen great Siddhars, is said to have originated in the Odhuvar clan. His Samadhi is said to be located in Azhagar Malai in Madurai district.

Machchamuni, the Siddhar, is thought to hail from the clan of the Pandiya, the Royal house. Since he carried the Flag of Fish or Machcha, the insignia of the Royal Pandiyan dynasty he is hailed as Machchamuni. He is said to possess many Siddhis and is revered as a Muni. Machchamuni Nigandu, Machchamuni Paadalgal are some of his creations. His Samadhi is said to be located in Thiruparangundram.

Gorakkar is the first Siddhar among the eighteen to have used Cannabis (Ganja) for its medicinal value. In appreciation of his work, cannabis is also called as Gorakkar Mooli. Chndhiraregai 200, Gorakkar Kannasooththiram, are some of his creations. His Samadhi is located at Perur in Coimbatore district.

One school of thought says that Azhugunni Siddhar has used Azhugunni and Thozhugunni herbs extensively in his works, and hence the reason for his name. Azhugan Vaiththiyam, Azhugan Yogam are some of his creations. His Samadhi is in Nagapattinam.

Punnaakkeesa Siddhar was also called Punnaakku Siddhar. The name was because he had a bifid tongue also called cleft tongue. He is said to have been born to Kannada parents. His Samadhi is said to be in Nangunacheri in present-day Kerala.

Kuthambai Siddhar was a Siddhar who was fond of Gnana Margam. He used the phrase “Kudhambaai” extensively in his creations and hence his name. His Samadhi is in Mayiladuthurai.

Idaikkaadar is revered as an avatar of Thirumal. He was an expert in the field of medicine like the God who created this universe. His fame could be gauged from the part called “Idaikkaadar Pinakku Theerththa Paadal” from Thiruvilayadal Puraanam. His Samadhi is in Thiruvannamalai.