The alarm sounded at dusk.
The "Demon Beast Tide" is not a natural phenomenon—it's hard to imagine several kinds of demon beasts foolishly rushing into an environment they are not adapted to at a particular time. Such foolish demon beasts should have been eliminated by natural evolution. It was an artificially created situation—or rather, a "Dragon-caused phenomenon."
As the overlord of the seas, the Dragon Clan's ruling status is etched into their bloodline. Millions of years of selection and evolution have shaped the unique social ecology of the Sea Demon Clan. This structure is similar to Earth's Xia Dynasty, where the Emperor holds supreme authority but generally does not manage his subordinates directly. Various states pay tributes, and any disobedient tribes are conquered by the Emperor.