They arrive in time of crisis and upheaval. Some say, that they are drawn to chaos; some others claim, that it is the other way around - a long period of stagnation causes the Chaos to violently strike back, and Dragon Kings are its embodiments. People always fear for the safety of what they have built, and at some point, stop taking chances, building ever-more complex systems to protect status quo. But the more complex a system, the more fragile it becomes to the forces of unknown and unknowable. An unthinkable combination of unlikely events happens, leading to catastrophe; a Dragon King rises.
>White Dragon freezes the world in a long winter, brings confusion and regress.
>Red Dragon burns it in a fiery breath of passions, revolutions, and infighting.
>Black Dragon shackles the world in irons and bends it to a single will.
>Blue Dragon brings euphoria and depression, making people to throw their possessions, beliefs and lives away.