I got an idea.
Earth is in 40k space.
I'm thinking of maybe the Dark Eldar, or the Slaugth, attack Earth first. Maybe the Slaugth. The Dark Eldar may pull in comparisms to the fair folk, but then there's always the problems of having a webway gate close by to earth, that can't be closed.
Let's start at the kuiper belt. The astronomers are the first to see it. After all, the Slaugth ship has already scouted the place, and know Earth has no way of fighting back. The ship passes through the solar system, slowly. It takes them about a week to do so. The feeling on earth is one of tension, fear, anticipation, excitement, and all the other feelings you get when you find out you're not alone in the universe.
There is some disgust, when the ship comes into orbit, and people see Slaugth technology for the first time.
They send out greetings. Radio beams and signals are sent to the ship, in greetings. The Slaugth only reply, telling them to surrender.
There is horror, and confusion. Then the bombardment starts. The military is smashed. Including the nuclear submarines.
The Slaugth then begin to land, and grab people for feeding, shown on live television. The world is horrified. The surviving military try to fight them off, but then are taken down by Slaught tech weapons. With lack of heavy armour, and not even access to mortars - remember, they bombarded the bases. That means no tanks and artillery. - they are helpless.
Occupation by the Slaugth goes on for 2 years, as the public feedings go on and on. The Slaught are seemingly sadistic, forcing men and women to watch as their children are fed on first, then forced to watch each other. Parents watch their children devoured. Wives see their husbands killed. Husbands see their wives eaten alive. All manner of cruelties are exercised. Mass executions are the norm. Those who displease the Slaugth, are, without an exception, converted via a slow and torturous process into one of their techno-organic technology, men, women, and children, all slowly transformed screaming into abominations.
Tribute is extracted, no matter the cost. Precious metals, slaves, manufactured machine parts, all countries have to pay, or be subject to bombardment. People starve and sicken as resources meant for food and medicine are not transferred to industry. People riot, or grumble, as their lives become worse and worse. And as the days pass, more and more resources are lost. Forests are cut down. Cities are empty. Lakes and rivers become polluted, filthy bogs. The skies are covered in smog.
There is resistance, but the punishment for collaboration is horrid. Families and friends of known resistance fighters disappear and are never seen again. Where the resistance fighters are seen, bombardment occurs. Armies of eye-searing drones of shining metal and meaty tendrils are sent to take down the fighters. The nations of the world are forced to fight down the only people fighting for them, under threat of death.
The situation is bleak. There is no way to shoot down the Slaught ship in orbit. There is no industrialized military machine to smash apart terrestrial forces. All electronics and satellites are analyzed and watched by the aliens. The majority of leaders have been killed, intimidated, or converted by the invaders. There is no discernible way for Earth to fight back.
Out at the edge of the solar system, a fleet of ships fleeing Hive Fleet Kraken exit Warp space....
