Dorje Shukden (Tibetan, rdo rje shugs ldan). A wrathful deity associated with the Gelukpa school of Tibetan Buddhism and regarded as its special protector. The cult of Dorje Shukden dates from the 17th century, and the deity is said to be the restless spirit (rgyal po) of Drakpa Gyeltsen, 1618-1655, a rival of Dalai Lama V who was driven to suicide by the latter's supporters. Initially only of minor importance, Dorje Shukden was elevated to the position of chief Dharma protector in the early 20th century, a development which led to sectarian rivalry within the Gelukpa movement in closing decades of the century when the Dalai Lama XIV urged Tibetans to cease to revere this deity. Most Gelukpas have done so, with the exception of Geshe Kelsang Gyatso and followers of the New Kadampa Tradition which he founded. The latter have rejected the Dalai Lama's appeal insisting on their right to religious freedom, a position that has caused a bitter sectarian dispute allegedly involving the assassination of Geshe Losang Gyatso, one of the Dalai Lama's leading supporters, and two of his students.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)