Where did it originate, and what is its significance today for practitioners?
Dorje Shugden is an emanation of the Wisdom Buddha Manjushri who arose as a Dharma Protector to fulfil a promise he had made in a previous life when as Duldzin Dragpa Gyaltsän, one of the principal disciples of Je Tsongkhapa, he promised to become a protector of Je Tsongkhapa’s tradition. This is explained by the Dalai Lama’s teacher and Gelugpa lineage holder, Kyabje Trijang Rinpoche, in his text called “Music Delighting the Ocean of Protectors” which can be downloaded here.