The Padma Purana says that that Dantavakra, King of Karusa, was of Caidya lineage. According to the Padma Purana Dantavakra was killed by Lord Krishna in Mathura. It has been referred in history that the Karusa royal family was connected by marriage not only with that of the Cedis but also with those of the Yadavas.
According to the historical accounts the Karusas had different settlements during different periods of history. In the Mahabharata the Karusas have often been mentioned along with the Matsyas, Kasis, Cedis and Panchalas. Vishnu Purana mentions them together with the Matsyas, Cedis, and Bhojas. It has been suggested that the country of the Karusas lay to the south of Kail and Vatsa, between Cedi on the' west and Magadha on the east enclosing the Kaimur hills, i.e. it was equivalent to the country of Rewa, from the Ken river in the west to the confines of Bihar in the east.
The Bala Kanda of the Ramayana would seem to indicate a slight difference of locality; it seems to locate the tribe in the district now known as Shahabad (Bihar) from where they probably had migrated from the south-west to the region indicated by the Mahabharata. According to tradition, the southern district of Shahabad between the river Son and Karmanaia was called Karukh-desa or Karushadesa. Moreover, Vedagarbhapuri or modern Buxar is referred to in the Brahmanandapurana as being situated in Karusa.
The Karusas probably had another settlement in the territory known in ancient times as Pundra, or Pundravardhana, roughly identical with North Bengal; for according to the Bhagavatapurana Karusa seems to have been another name for Pundra.
In the Vayu, Matsya and Markandeya Puranas, the Karusas are said to have occupied the ridge of the Vindhyas (Vindhaprstha-nivasinah). In the Markandeya Purana, they are mentioned along with the Keralas and Utkalas, and in the Brahmandapurana with the Malavas, Utkalas, and Dasarnas while in the Vishnu Purana they are associated with the Arbudas and Malavas. Further, the Vishnu Purana definitely refers to them as dwelling along the Paripatra hills. In the Bala Kanda of the Ramayana the Karusas and the Maladas are named together.
Historical records state that the Karusas figure in the Kurukshetra war along with the Kekayas, Panchalas, Matsyas, Cedis and Kosalas, who rallied on the side of the Pandavas. At one time during the war, the Cedi, Kail, and Karusa people seemed to have been led by Dhristaketu, King of the Cedis. Another King of the Cedis was Vasu, a descendant of Kuru, who having conquered the Yadava kingdom of Cedi extended his conquests eastwards as far as Magadha, and apparently north-west also, over Matsya. He had divided his territories of Magadha, Cedi, Kausambi, Karasa, and Matsya among his five sons.