Evidently a creation of Alice Bailey (1880-1949; she split from the Theosophical Society in 1920), channeled by her (see article on her in Citizendium). He telepathically dictated some of Alice Bailey's books (18 altogether), including one on sex. It has been speculated (for example in Wikipedia entry) that his name is actually Sanskritic, coming from jvala and kula. It certainly doesn't look like Tibetan at all, although he is often called "The Tibetan." No information is supplied about him, except that he is head of a monastery in northern India on the borders with Tibet. I'm reminded of Jwalakhel, which nowadays has a Tibetan refugee settlement in Nepal, but see no special reason to assert that this similarity means anything.
David Reigle, D.K. and Kalachakra, published in The Beacon, issue for January-February 1991. Also placed on the internet for free download.
David Reigle, On the Alleged Tibetan Source of Alice Bailey's Writings, published in Fohat, vol. 1, no. 1 (1997). Also placed on the internet.