Lama Losang Tubwang Dorjechang
Lama Losang Tubwang Dorjechang is a special manifestation of Je Tsongkhapa revealed directly to the great Yogi Dharmavajra.
Je Tsongkhapa appears as a fully ordained monk, with Buddha Shakyamuni at his heart, and Conqueror Vajradhara at his heart. In the practice of Offering to the Spiritual Guide, we visualize our Spiritual Guide in this aspect.
'Lama' indicates that he is our Spiritual Guide, 'Losang' that he is Je Tsongkhapa (whose ordained name was Losang Dragpa), 'Tubwang' that he is Buddha Shakyamuni, and 'Dorjechang' that he is Vajradhara.
This indicates that in reality our Spiritual Guide is the same nature as these three holy beings. For more information, see the book Mahamudra Tantra.