Is Bianca the younger brother of the Four Seas Dragon King?

The four dragon kings are not brothers.

The first thing to understand is the Four Seas Dragon King, not a brother, but a sworn brother. Aoguang, the king of four great dragons in the Middle East, is the largest, followed by Aoqin, Aoshun and Aorun, the dragon king of the South China Sea. They are descendants of four dragons.

These four dragons are the Dragon King of Di Qing in the East, the Red Dragon King of Chi Di in the South, the White Emperor Bai Longwang in the West and the Black Dragon King of Hei Di in the North. Since the Tang and Song Dynasties, emperors of past dynasties have issued imperial edicts to Dianlong many times, making it king, and all four dragons have been sealed.

Of course, there is also a central yellow emperor, Huanglong King, that is, Ying Long, who has not been posthumously sealed. Why? Because the emperor claimed to be the real dragon emperor, the dragon in the middle could only seal himself.

It can be seen that the emperor pretends to be the real dragon emperor, and he represents the highest level dragon, that is, Ying Long, and the four dragon kings are all lower than Ying Long, so they are all dragons.