K'da

The K'da are a fictional race from the Dragonback series written by Timothy Zahn.

The K'da are a race that come from another spiral arm of our own galaxy, and are only in our part of it due to an attack by another alien species. They resemble the dragons of myth, and are reptilian. In order to survive they must BOND to a host, usually of a race called the Shontine but humans work as well, and if they do not they will die in six hours, slipping into another dimension. By bonding to a host they paste themselves on the host's skin, much like a tattoo, and are described as being in a fourth dimension, though as three-dimensional beings we see it as them becoming two-dimensional and flat.

They have black blood instead of red, and their scales become black while they are angered or distressed. They are as intelligent as humans, and sometimes more so. They follow a strict ethnic code, much like the knights' chivalry, and not adhering to this code is blasphemous.