CADDO is an icy moon of Bole which is occupied by a militaristic sect of that planet's Hakuraku society.  They emigrated to avoid the necessity of living almost entirely in protective darkness, but they are sworn to protect their brethren and the brightly-glowing orb that dominates their night sky.  Fortunately there have been no overt threats to Bole, although whether this is due to their protection or otherwise has not been demonstrated.  Their most remarkable achievement is the development of a chemical matrix called "yaoshu" which allegedly imparts knowledge directly into a person's brain after it has been absorbed through the skin during a ritual "Spirit Dance".  The yaoshu chemicals are said to be carefully "programmed" with whatever skills and memories are needed for a person's role in the society.  One constant among all those patterns is a keen and constant desire to remain on Caddo and serve the Hakuraku faithfully.  At least this is the observed behavior of all whose curiosity has compelled them to take an oath before taking a yaoshu treatment.  Perhaps they are being compelled by threat of force rather than a force of will, but no one has ever abandoned Caddo.