Tirumular was a travelling Shaiva saint and solar from Kailash (திருமூலநாயனார்)

Legend has it that Tirumular was a travelling Shaiva saint and scholar from Kailash who used his yoga powers to transmigrate into the body of a southern cowherd, Mulan.18 Siddhar and meditation techniques He woke up from his yogic trance once a year and composed one verse until he attained salvation.

The dates of Tirumūlar's life are hotly contested and, because his work makes reference to so many currents of religious thought, the dates that different scholars assign are often appealed to for anchoring the relative chronology of other religious literature in Tamil and Sanskrit. Verse 74 of the Tirumantiram makes the claim that Tirumūlar lived for 7 aeons (yuga) before composing the Tirumantiram
 தெளிவுறு ஞானத்துச் சிந்தையின் உள்ளே
அளியுறு வார்அம ரர்பதி நாடி
எளியனென் றீசனை நீசர் இகழில்
கிளியொன்று பூசையின் கீழது வாமே.

யாவர்க்கும் முதல்வனாகிய சிவபெருமானது திருக் கோலத்தின் உண்மைகளை நூல்களாலும், நாட்டில் அமைந்த திருக் கோயில்கள், அவற்றில் நிகழும் விழாவகைகள் முதலியவற்றாலும் ஓர்ந்துணர்ந்து, அதனால் தெளிவுபெற்ற ஞானத்தை உடையராய் உள்ளத்தில் அன்புமிகப் பெறுவோர் பின்னர்த் தேவராவர். அவ்வாறு ஓர்ந்துணரவும், தெளியவும் மாட்டாத கீழ்மக்கள் அப்பெருமானை, எலும்பு, தோல், சாம்பல், வெண்டலை முதலியவைகளை உடைய வனாய்ச் சுடுகாட்டில் ஆடுதல், தலையோடு ஏந்தி இரத்தல் முதலிய வைகளையே நோக்கிச் சிறுதெய்வமாகக் கருதி இகழ்வார்களாயின், அச்செயல், கிளி ஒன்று தானே பூனையின் அருகுசென்று அகப்பட்டு நின்றது போல்வதாய்விடும்.

Agastyar Maha Munivar (அகத்தியர்)

He is considered as the first and foremost Siddha. He is considered the guru of many other Siddhas. He is also called Kurumuni, meaning short (kuru) saint (muni). He made contributions to the field of Medicine and Astrology - especially Nadi astrology. He is said[Tamil sidhhars] to have lived for over 5000 years, and that one of his medicinal preparations, Boopathi Kuligai, is so powerful that it can even bring the dead back to life. Two of his students and disciples were Therayar and Tholkappiar. Another story about him is that once when the great sage accompanied by his beloved royal wife were wandering through forests, she fainted due to the humidity and hot conditions prevailing in the south. She was royal, hence not exposed to hard conditions. By seeing this the great sage became angry and prepared to punish the Sun God with his bow and arrows. Upon seeing this the sun god feared and appeared before Agastya and presented him with umbrella and chappals (foot wear).

Bhogar (போகர் சித்தர்)

Bogar is a Siddhar, he is considered as one of the 18 siddhars born in the world. According to epigraphical sources and his book Bogar Seven thousand his period is around 3000 B.C. Bogar born at India and visited China in search of truth of life, he gained knowledge in medicine, astrology, spritiuality, yoga etc.

Bogar anticipating that in due course of period, human beings will suffer from large number of disease. As an expert in medicine he used 4448 rare herbs and made 9 poisonous medicine, mixing these 9 poisons into one needs great knowledege and skill, to make a Master Medicine ( One medicine to cure all disease ). Thirumoolar also discuss one such Master Medicine in his book Thiru Mandiram. With the consultation of Agasthiar ( Father of Ayurvedic Medicine) and other siddhars Bogar mixed the 9 poisons ( Nava Bashanam ) and made the Master Medicine in the form of Lord Murugan which is currently worshiped at Palani Murugan temple. There is a place near Palani Hill called Thanasiappan Temple which is the place were Bogar mixed the Nava Bashanam and made the Murugan idol.

Notes and references:http://palani_murugan.tripod.com/bogar.htm