Dromton's teacher was the disciple of a man who was one of how many Buddhist Mahasiddhas?
Ratnākaraśānti Ratnākaraśānti (also known as Śāntipa) (c. 1000 CE) was one of the eighty-four Buddhist Mahāsiddhas and the chief debate-master at the monastic university of Vikramashila. At Vikramashila he was instructed by Nāropa, and taught both Atiśa and Maitrīpa. His texts include several influential commentaries to Buddhist tantras, as well as works of philosophy and logic.
Mahasthamaprapta Mahāsthāmaprāpta is a bodhisattva mahāsattva that represents the power of wisdom, often depicted in a trinity with Amitābha and Avalokiteśvara (Guanyin), especially in Pure Land Buddhism. His name literally means "arrival of the great strength".