Blood-consort

Blood-consorts are the spouse or mate of a reigning blood-sovereign. Specifically in The Bone Season, it is the husband or fiancée of the blood-heir to the throne.

Description
The Rephaim have no concept of marriage, but the first mating of the blood-sovereign and blood-consort formalizes their union. So when Warden says he was "betrothed" to Nashira, he means that he was her chosen consort, but had not yet mated with her.

Known Blood-consorts

 * Arcturus Mesarthim to Nashira Sargas of the Rephaim.