Who is Siddha(r)?

Who is Siddha(r)
Siddhars are saints in India,mostly of the Saivaite denomination in Tamil Nadu,who professed and practised an unorthodox type of Sadhana,or spiritual practice,to attain liberation.Yogic powers called Siddhis are acquired by

 constant practice of certain yogic disciplines.Those who acquire these Siddhis are called Siddha.Siddhars are people who are believed to control and transcend the barriers of time and space by meditation (Yoga),after the use of substances called Rasayanas that transform the body to make it potentially deathless,and a particular breathing-practice,a type of Pranayama.Through their practices they are believed to have reached stages of insight which enabled them to tune into the powers hidden in various material substances and practices,useful for suffering and ignorant mankind.Typically Siddhars were saints,doctors,alchemists and mysticists all at once.They wrote their findings,in the form of poems in Tamil language,on palm leaf which are collected and stored in what are known today as Palm leaf manuscript,today still owned by private families in Tamil Nadu and handed down through the generations.

Powers of siddhas
To become tiny as the atom within the atom (Anima)
To become big in unshakeable proportions (Mahima)
To become as light as vapour in levitation (Laghima)
To become as heavy as the mountain (Garima)
To enter into other bodies in transmigration (Prapti)
To be everywhere in omnipresence (Vasitvam)
To be in all things,omni-pervasive (Prakamya)
To be lord of all creation in omnipotence (Isatvam)