Tamdin Yangsang (Haya Griva) is the protecting deity of Sera Jey Monastery. It was rightly given this place by venerable Kunkhenpa Lodroe Rinchen Senge, after significantly experiencing various forms of divine predictions and auspicious symbols, which led him to accept and initiate in the worshipping of this sacred and divine deity.

Haya Griva is the wrathful characteristics of Chenre sig (Avalokteshwara). The deity is well known for its supreme power in removing obstacles and also for its healing power. Tokden Yonten Gonpo, father of Kunkhepa, a learned and firm devotee of Haya Griva deity, during the final days of his life, had offered to is beloved son the complete teachings of Pema Yangsang & Tandin, with the advice to commit oneself in complete devotion & follow them. 

Kunkhenpa, as one of the most dedicated disciple of Lama Tsong Khapa, sought the virtuous advice and consent of his master. The all-knowing noble master laid his hand on the head of his learned disciple & scholar, blessing him to give his approval. An indentation mark of the saintly master's palm was left on the head of the devoted pupil Kunkhenpa. Thus leaving a memorable legend to the history of Tamdin Yangsang /Haya Griva's emergence as the sacred deity of Sera Jey Monastery. From thereafter, Kunkhenpa institutionalised Tamdin Yangsang / Haya Griva as the Deity of Sera Jey Monastery.