On the mountainous road to Riddi kshetra from Palpa, one can see the beautiful yet barren valley said to be called as Mandukya rishi kshtera. This was the place where Manduka muni was doing penance and was wrongly caught by king’s guards. Later he went on to curse Yamraj for wrongly punishing him. As a result, Yamraj came down to earth and took birth as Vidura. After this incident, this place of muni also became barren on account of the curse.
The detailed story is mentioned by Srila Prabhupad in his Srimad Bhagavat 1.13.1 commentary and purport as follows: Once upon a time the state police caught some thieves who had concealed themselves in the hermitage of Maṇḍuka Muni. The police constables, as usual, arrested all the thieves and Maṇḍuka Muni along with them. The magistrate specifically punished the muni to death by being pierced with a lance. When he was just to be pierced, the news reached the king, and he at once stopped the act on consideration of his being a great muni. The king personally begged the muni’s pardon for the mistake of his men, and the saint at once went to Yamaraj, who prescribes the destiny of the living beings. Yamaraj, being questioned by the muni, replied that the muni in his childhood pierced an ant with a sharpened straw, and for that reason he was put into difficulty. The muni thought it unwise on the part of Yamaraj that he was punished for his childish innocence, and thus the muni cursed Yamaraj to become a sudra, and this sudra incarnation of Yamaraj was known as Vidura, the sudra brother of Dhṛitaraṣṭra and Maharaj Paṇḍu