A few newbie questions.

[ComTrav]

"Blood economy" is the collection of blood slaves. It's easier to capture blood slaves in high population provinces, but blood hunting increases unrest and reduces population. Hence, a "blood economy" is fundamentally opposed to a "gold economy".

The big blood nations are EA/LA Mictlan and Lanka, although lots of nations have smaller blood picks (the "'heims", LA Marignon and Ulm, Pangea, come to mind)