This manga is about a girl named Mulan, who donned armor in her aged father's place and came to serve in the Sui Dynasty's expedition to Gao Ju Li (Korea). However, due to a revolt caused by Imperial corruption, there came an event which would greatly change the course of her fate!!

In ancient times, at a lake somewhere in the middle of Eurasia, lived people (ハムランムル) with the ability to transform into animals. But soon internal quarrels forced the population apart into four tribes, which then scattered all over the world. Their descendants prospered, including a certain Hidaka, a high school student who would be completely unremarkable if not for his unnatural appetite.
However, a British aristocrat, Earl Linford, wishes to subjugate all clans by establishing the supremacy of his own blood. For he can, after all, transform into a lion, the king of the animal reign.
That is when Renée, a young woman who can turn into a beautiful wolf, enters the picture and endeavors to return Hidaka to his roots.
(Source: jCafe24)

The story features four divine Dragon Kings, each with their own kingdoms: one to the north, one to the east, one to the south, and one to the west. The brothers are reborn in the modern world, complete with supernatural powers and the ability to become the Dragons they descended from. They are content to live ordinary lives until evil creatures come to attack them.
It becomes the mission of the four brothers to defeat the "Four Sisters", four girls from America and the descendants of the "Bulls", before they use their control over technology and the economy to take over the world. However, as this battle begins, the four brothers must also find their place in the world as they flee from the destructive will of the "Bulls".