As I discuss in my question here, the Matsya Purana describes various incarnations that Vishnu has taken in the Vaivasvata Manvantara (i.e. the present Manvantara). In particular, here is what it says about an incarnation of Vishnu that took place at the time when the Chakshusha Manvantara was ending and the Vaivasvata Manvantara was beginning:
In accordance with that ordinance of Brahma, there was a partial incarnation of Narayana as Dharma at the end of the Chakshusha Manvantara, when the Devas performed a sacrifice in the beginning of the Vaivasvata Manvantara. At this incarnation Brahma was the officiating priest. This was the first incarnation [of the Vaivasvata Manvantara].
This excerpt from the Prabhasa Khanda of the Skanda Purana says the same thing:
He took the incarnation to establish piety (Dharma). Narayana should be realized through Dharma (piety). He was then born in the Chakshusha Manvantara. He propagated Yagna in the Vaivasvata Manvantara. At the time of his manifestation, Brahma became his priest.
I discuss this "officiating priest" business here, but my question is, what is he story of Vishnu's incarnation Dharma? Who were his parents, and how did he "propagate Yagna"? Is that related to his involvement in the Yagna conducted by the gods?
Is it possible that he's the same as Yama god of death, who I think was born in the Chakshusha Manvantara? Is Yama ever described as an incarnation of Vishnu?