Sage Agathiyar is considered the guru of all Siddhars, and the Siddha medicine system is believed to have been handed over to him by Lord Muruga, son of the Hindu God Lord Shiva and Goddess Parvathi.Siddhars are the followers of Lord Shiva. Agathiyar is the first Siddhar. He is also known as Kumbamuni and Gurumuni.