According to the "Rig-Veda," Yama is considered to be the human ancestor because the human race was born of Yama and his sister Yami; he became the king of the world of the dead because he was the first human being to die.
『リグ・ヴェーダ』では人間の祖ともされ、ヤマとその妹ヤミーとの間に最初の人類が生まれ、人間で最初の死者となったゆえに死者の国の王となった。