Minax

A Minax is a dark spirit, said to be created by Eurus, the god of the east wind. However, all but two were imprisoned by his sister Cirrus, the goddess of the west wind. The other two were put, by Eurus, in the Fire Throne and the Frost Throne, where they have been influencing many rulers and pushing them toward war with the other race.

Minaxes can also possess people. When a person is possessed fully by a Minax, their blood turns black. It is also said that they see in black and white, not in shades of color.

No one who has been possessed by a Minax lives for very long, except for Ruby, the main protagonist of the series. She is called the "True Vessel" of the Minax. It is also later revealed that Eurus created her as the first of a new race, a "Nightblood". Nightbloods are able to host the Minax without dying. Eurus plans to free the rest of the Minaxes, but he says that he needs a Nightblood there to help him.