The Chosen believe that it is primarily their blood that sets them apart from other beings. It is in their blood that their semi-divinity resides, derived ultimately from descent—however partial—from a God Emperor.The Chosen believe that, at his Apotheosis, a new God Emperor receives the ‘essence’ of the Twin Gods and, in the process, his mortal blood is transmuted into pure ichor: the divine, the burning blood. Any child fathered by a God Emperor receives the gift of this ichor intermixed with the blood of its mother.

Deriving ultimately from a God Emperor, each of the Chosen carries a proportion of this ichor in his/her veins. The fraction of blood which is not ichor is called his/her Blood-Taint and is calculated in quyan fractions by the Wise, who record in their Books of Blood. This blood-taint is inscribed along the edge of a blood-ring that is given to each of the Chosen at his/her coming of age. This ring is made of precious iron, whose smell and rust symbolize ichorous blood. Such rings can be used as seals with ink and wax.

Further, each of the Chosen has the blood-taints of his/her mother and father marked on their back with scarring combs. This marking is carried out by the Wise at the child’s birth. The father’s taint is put on the right side of the spine: the mother’s on the left.

A Blood-Rank is the number of serial zeros in a blood-taint fraction before a non-zero is reached. Anyone with at least one zero (in the first position) is considered to be of the Great. One zero confers blood-rank one; two zeros blood-rank two and so on. A blood-rank of three is rarely found outside the House of the Masks—the God Emperor’s own House. Blood-rank four is very high indeed and indicates a blood-taint with zeros in the twentieths, the four-hundredths, the eight-thousandths and the one hundred and sixty thousandths. Ykoriana is the first woman for generations with such pure blood.