While Harry is sleeping he is inundated with visions of the future and of the past.
If a well off nation exploits its immigrants, they will end up like the Mongolian Empire, and expand to the immigrants home worlds and set up a large empire. But in time the home nation will dwindle, as the mass multi-culturalism will wipe out the spirit of the original nation. This is if the immigrants are exploited like in the Mongol Empire.
If Earth accepts a wide multi-cultural influx, and exploits them, then Earth will be at the center of a small intergalactic empire. To avoid this, Earth must have the immigrants as the exploiters.
A small example is playing out with the American magical world. They are exploiting immigrants from central and south Amereica as well as central Africa. All those regions have governments based off the USA model. If the Americans accept mass multiculturalism where the immgrants are gravely exploited like the slaves of the Mongols, the future holds the USA conquering all those regions, and instilling a new empire.
But in time the original founder spirit of the Americans will dwindle and fade, until not only even the legacy, like the Mongols, is left behind.
The Americans already have their small empire, with the governments based off theirs in south American and Africa, and they already exploit immigrants from those areas. To reverse this empire building, the USA must allow immigrants from those areas to be the exploiters and change the narrative.
But that is just a small scale of what could happen to Earth upon contact.
To avoid becoming the heart of an empire, in which the spirit of Earth will dwindle before dying off by exploiting immigrants, Earth must take affirmative action for immigrants. This affirmative action is not for positive sections, such as tax collection, public health, or other sectors that help the people. This affirmative action is only for exploitive industries, such as positions in an unregulated toxic financial system, in private health care, or in advocating for mass weaponization of the public. And if there ever is any charity given to them, they are expected to never give a quid pro quo, and instead just take and exploit the charity givers. Some kind of productive vice, there should be affirmative action for immigrants to be placed in them. While there is affirmative action for a vice, there should be rampant discrimination against the immigrants in sectors that help the people, such as farmers, non-tyrant government jobs, blue collar jobs, and such.
The purpose of this is for the productive vices to be something to be rebelled against by the Earthlings and then replaced with something that also provides cohesion but at a much smaller cost.
A small scale example of this is the money lending of the middle ages in Europe, where immigrants provided the loan shark rates, while the natives were the victims of the loans. Rampant discrimination for employment in guilds that provide public good were in place, but affirmative action in the exploitive industries were also in place.
A large scale example of this is the settlers of the New World. The natives are the ones being consistently exploited by the immigrants. There is affirmative action for immigrants to exploit the natives, but there is rampant discrimination against the immigrants for practices that help the native people. In modern history, the leaders of the New World nations were tyrants to the people, which are the natives. There is affirmative action for immigrants to be tyrants. But there is great discrimination for a leader of the New World to be helpful for the people. The position of a president or prime minister or governor general that helps the natives is reserved for a native.
In both cases, the people refers to the natives, while the immigrants remain separate.
In both cases, the people rebel against the immigrants with better ideas to produce faith instead of productive vices. That is the limiting factor for the people; the new unduplicable solutions to produce faith for them that replaces a productive vice of the immigrants.
In either case, that is the future of Earth.
Dark Lords are meant to be defeated, in exchange for the heroes developing some new way to produce cohesion without the vice. In exchange, the villain is remembered. Being remembered is a form of resurrection. A Dark Lord and their prominent followers are remembered by the heroes. The villains are in a tight competition with other villains, as vanity fuels a Dark Lord and their followers, while efficiency fuels their competitors. Dark Lords are always inefficient, to allow the hero to come up with a solution to defeat him. Dark creatures just want to win, while a Dark Lord looks to lose, but to extract as much power or normalcy from their fall as possible.
"Harry, you should be a Dark Lord for all of Earth: join the alien immigrants, and be what the Earthlings rebel against. And in the meantime, practice with the American Natives, be a Dark Lord to them."
Harry woke up with a start and looked around the room. No one is there.