In Hindi he is called both Yamaraja as well as Dharmaraja. Both words have their meaning which applies well.
Yamaraja means the one who restrains, the King who Restrains the journey of life and keeps it within limits.
Dharmaraja means the guardian of the Law, the King who keeps the Law and thereby ensures some kind of balance. He is the guardian of the Law of Ignorance. There is a greater Law, the Law of Truth and Light, Satyadharma of which Yama is the Shadow.
