On the stage in Chennai where C Joseph Vijay took oath as Tamil Nadu Chief Minister on Saturday, one of the new ministers who drew attention was Aadhav Arjuna, the ambitious political operator who had travelled through the DMK, the VCK, and finally the TVK, before landing at the centre of the state’s new ruling arrangement. Watching from the audience was his father-in-law, and lottery baron, Santiago Martin, mother-in-law Leema Rose Martin, and wife Daisy. Elsewhere in the political map sat another layer of the same family: Leema Rose Martin, now an AIADMK MLA in Tamil Nadu and Arjuna’s brother-in-law Jose Charles Martin, founder of BJP ally Latchiya Jananayaga Katchi (LJK) and a newly elected legislator in Puducherry and likely, a minister soon. Few business families in South India today appear as politically diversified as the Martins.…