Mahavatar Babaji’s role on earth:

  The Mahavatar is in constant communion with Christ; together they send out vibrations of redemption, and have planned the spiritual technique of salvation for this age. The work of these two fully-illumined masters–one with the body, and one without it–is to inspire the nations to forsake suicidal wars, race hatreds, religious sectarianism, and the boomerang-evils of materialism. Babaji is well aware of the trend of modern times, especially of the influence and complexities of Western civilization, and realizes the necessity of spreading the self-liberations of yoga equally in the West and in the East.

In addition, Babaji is reputed to be ageless, according to some accounts, and about 500 years old around the late 1800's, according to Swami Pranabananda. Yogananda reports that, according to the disciples of Lahiri Mahasaya, nobody knows Babaji’s age, family, place of birth, true name, or other details “dear to the annalist’s heart."
According to Yogananda's Autobiography, he has a sister called Mataji (meaning "Holy Mother") who also has lived throughout the centuries. Her level of spiritual attainment is comparable to her brother's, and she lives in a state of spiritual ecstasy in an underground cave. Although only three pages in the book are dedicated to her, she is described by Ram Gopal as "young and surpassingly lovely" as well as a "glorious woman."