The East Sea Metropolis population was over one million, which served as a great boost to William's source of soldiers.
Taking into account the civilian populations of the Black Lava Dukedom and the City of Dawn, the overall population under his rule had reached 3 million.
No race other than the humans lived at the East Sea Metropolis.
This city located by the coast had always been reliant on fishery and agriculture to boost its economy.
Of course, there were other factors too.
There existed some rare ores and resources that were also very profitable. It was these things that made the vampires of East Sea Metropolis filthy rich.
Immortal creatures like vampires were extremely similar to human aristocrats.
They were fond of antiques, oil paintings, statues, and other expensive but useless artworks.
Otherwise, William could have pilfered more than 2 million gold coins.