From Sanskrit, Sanatkumar सनत्कुमार, "eternal youth." Founder of the College of Initiates of the White Lodge, a venerable elder mentioned in very ancient religions. Sanat Kumar is one of the four kumaras, the Four Thrones of which the Bible speaks. Three are gone and only he remains.
"Let us remember Sanat Kumara, the Ancient of Days, the great immolate, the founder of the College of Initiates of the great White Lodge. This adept lives in the Gobi desert in an isolated oasis. The body of this great being is more than 18 million years old. With him, in the same oasis, live a group of adepts with immortal Lemurian bodies." Samael Aun Weor, The Mysteries of Life and Death
"The Kumaras," explains an esoteric text, are the Dhyanis, derived immediately from the supreme Principle, who reappear in the Vaivasvata Manu period, for the progress of mankind." ... "these sages live as long as Brahma; and they are only created by him in the first Kalpa, although their generation is very commonly and inconsistently introduced in the Varaha, or Padma Kalpa" (the secondary). Thus, the Kumaras are, exoterically, "the creation of Rudra or Nilalohita, a form of Siva, by Brahma, and of certain other mind-born sons of Brahma. But, in the esoteric teaching, they are the progenitors of the true spiritual SELF in the physical man -- the higher Prajapati, while the Pitris, or lower Prajapati, are no more than the fathers of the model, or type of his physical form, made "in their image." Four (and occasionally five) are mentioned freely in the exoteric texts, three Kumaras being secret. The Exoteric four are: Sanat-Kumara, Sananda, Sanaka, and Sanatana; and the esoteric three are: Sana, Kapila, and Sanat-sujata. Special attention is once more drawn to this class of Dhyan Chohans, for herein lies the mystery of generation and heredity..." - H.P. Blavatsky, The Secret Doctrine