The term "Mahavatar" stands for "great incarnation" and Mahavatar Babaji is regarded as the "respected father". Mahavatar Babaji, also known as Shiva Baba, Nagaraj and Kriya Babaji is one of the most esteemed Sadhakas. He possessed strong and magnanimous supremacy of soul. It is said that that his body had not aged since the age of sixteen and was in acquisition of 'youth of 16 summers'. Babaji is said to be the "atmik guru" who could transform his body on any shape he wished.

Babaji was born in 562 B.C in Parangi Pettai, Porto Nova, now a small village near Cuddalore in Tamil Nadu, India. Babaji was christened, Nagaraj by his parents, which connotes the meaning the king of serpents. Babaji's father was a priest at a Shiva temple. Babaji's birthday falls on the day when the Pushya Star is in operation on the month of Karthika.

The personal information about Mahavatar Babaji is vague. He is said to be the guru of Lahiri Mahasaya. The book Autobiography of a Yogi" by Paramhansa Yogananda reveals some of the characteristics and incidents of Babaji's life. According to the modern references and claims, Mahavatar Babaji, a legendary person was witnessed by a number of disciples during the time from 1861 to 1935.

Mahavatar Babaji, the originator of Kriya Yoga, mastered "death" and reached the predominant state of wisdom. Being the guru of Adi Shankaracharya, Mahavatar Babaji was described in a poem as Dakshinamurti, a youthful teacher who was surrounded by his followers under a banyan tree. Babaji was described as a "tnaha avatar", a great avatar, the Sanskrit word carrying the meaning incarnation of the godhead in human form, by Sri Yukteshwar, the guru of Yogananda.

It has been mentioned by one of the tradition that Babaji in the form of Badrinarayan traveled a long pilgrimage to Badrinath which is the ancient temple of Lord Vishnu. He mastered the yogic methods from his gurus and in the course of time entered the state of "Samadhi" which is defined as the state of complete decadence of divinity and the transformation of the mental , physical, intellectual and spiritual phases of a human soul and anatomy. He preceded the human race to move towards realization of God.