The Caldari bloodlines refer to the two distinct races that emerged on Caldari Prime, the Deteis and Civire.
Back in the days when the the Caldari occupied Caldari Prime, each bloodline developed on a separate continent and was very distinct both physically and culturally. At the start of the war with the Federation the Caldari race was uprooted as a whole and thrown into a melting pot where fighting for their survival was all that mattered. The frantic decades that followed altered the Caldari psyche forever. Discipline and loyalty came to the forefront and still shapes Caldari society into something new. Currently people in the State identify themselves as Caldari first, their corporation second, and their bloodline a distant third. None of the megacorps are structured around bloodlines and they intermingle freely on every level. Even so, intermarriages are rare, but this is thought to be more a matter of physical preference. Although the individual bloodlines are proud of their heritage, it ranks low in importance.