This is a word that relates to the Game of Thrones series, in which "the iron price" was described as paying for something with blood, either
one'
s own, or anothers. Iron is a major component in the make-up of a person's blood, and the iron price clearly relates to this; versus paying for something with
gold, silver, or something else. See also, the Iron
Bank of Braavos, which has a similar concept relating to it.