Story Of Dantavakra is found in the Vishnu Purana, Mahabharata and some editions of Srimad Bhagavad Purana. Dantavakran or Dantavaktran was the incarnation of Vijaya who along with Jaya were the gatekeepers Vaikunta. They were cursed to be born on earth as demons in each yuga. In Dwapara Yuga, when Sri Krishna was on earth they were born as Shishupala and Dantavakra.
As per Padma Purana (VI.274.16-7), he was a king of in the Chaidya lineage.
As per Vishnu Purana, his mother was Shrutadevi, who was the sister of Kunti, mother of Pandavas, and Vasudeva, father of Sri Krishna.
As per Vishnu Purana (IV.XIV.40) and Srimad Bhagavata Purana (X.78.5-6) his father was Vriddhasharman. Shishupala was a relative of Dantavakra.
Dantavakra was a friend and ally of Shishupala, Jarasandha, Kamsa, Salva and Paundraka. He always considered Sri Krishna as his enemy.
As per Mahabharata, he was defeated by Sahadeva. The Pandavas gave back his throne after he accepted the emperor status of Yudhishtira. But he did not participate in the Rajasuya Yagna to protest the killing of Jarasandha.
To avenge the killing of Shishupala by Sri Krishna, Dantavakra attacks Sri Krishna who was returning after participating in the Rajasuya Yagna of Yudhishtira at Indraprastha.
In the battle, first Viduratha, brother of Dantavakra, gets killed. Sri Krishna and Dantavakra indulge in a fight of maces. Sri Krishna easily overpowers Dantavakra and kills him. Thus, Vijaya gets moksha and attains his spot in Vaikunta.