There was a war, of course. Only in the the magical Britain at first but muggles started to feel its effect soon enough as well. During this time, Harry and his queens limited themselves to a few covert operations. Their stunt with the submarine panicked a lot of people so it was better to lie low. Harry didn't know whether other nuclear powers were appraised of the situation but the fact remained that the submarine was being searched for.
It didn't take long for the Ministry of Magic to fall. With people like Dumbledore and Moody gone, there was no one left to stand against the magic of the likes of Voldemort, Barty, Bella, and others.
Eventually, the war spilled over to non-magical world. It was a messy situation filled with chaos and destruction. Surprisingly enough, Harry didn't have to orchestrate it - it was all part of Voldemort's design. Maybe the two "great" minds thought alike?
Harry and the queens contemplated the situation. It was decided to stay their hand for the moment and deploy their nuclear weapons at the right time, at the right targets.
Alas, the events were faster than them. An idea started to brew in United States to take a radical action. Maybe it was because they were so nervous about their missing submarine and suspected Voldemort's forces of the theft. Maybe they didn't believe their wizards who insisted that the Dark Lord didn't even know what a nuclear bomb was.
And so the Dark Lord made the first move. It was unknown whether he knew about the missing submarine and wondered who stole it. What was obsoletely certain was the fact that he was perfectly aware how United States and other nuclear powers felt. While he had seized control over British nuclear silos, in fact, and knew how to use them, he was certain that it was the idea of magic that scared them the most (or at least every bit as much as the idea of nuclear weapons in the hands of terrorists).
Before nuclear powers could agree on a nuclear strike against Britain, Voldemort launched his missiles. Not at the United States but at Russia of all targets. Yes, they were a threat, but his plan was to trigger a global nuclear war. He assumed that if an ally of USA launched a nuclear attack on Russia, it would retaliate.
Or did he? Russia obviously knew about the situation in Britain and about the planned American attack. So, instead of Americans and Russians launching missiles at each other, they annihilated Great Britain instead.
What exactly had been Voldemort hoping to achieve is unknown. Maybe he had always intended to destroy Britain. Maybe he didn't expect Hogwarts and other important places to be destroyed, which was exactly what happened (unplottability does have its limits). Maybe he fled to continental Europe or to America, like Grindelwald decades ago.
Whatever he had planned was most probably derailed by what Harry did afterwards. His submarine was in South China Sea at the moment, dodging a few pursuing American attack subs. It was an explosive situation from a diplomatic point of view. Harry didn't know whether the Chinese government had been told about the stolen submarine and whether they believed the story. He suspected that they were aware that there were American submarines operating in their backyard and that they deployed their own ones.
He knew what he needed to do to trigger a global nuclear war. He rigged the reactor to meltdown and launched all his missiles at China. They abandoned the ship quickly.
China could have shown restraint like Russia. Unfortunately, the world wasn't meant to be so lucky twice in a day. They launched their own weapons against USA and a chain reaction was started.
In a short time, all major cities in the world were destroyed. It was all the nuclear apocalypse people had always imagined. When the radioactive dust settled, Xenomorph queens began their campaign to conquer Earth. Harry wasn't sure where Voldemort was or if there were any powers left to oppose them but it didn't matter. If they waited too long, wizards, vampires, or goblins would establish their own reign over the planet. At the moment, all of those were still getting their bearings after the nuclear holocaust.
In first couple of days, they limited themselves to kidnapping people and using them to bolster their ranks. Many of them were irradiated but that hardly mattered. Among the taken were quite a few magical people who lived aside from larger magical settlements. Harry oversaw those attacks personally - a wizard was formidable foe, even for their kind.
Afterwards, while the new drones were still hatching, they made their first series of proper strikes. Facilities with remaining nuclear weapons, conventional military bases, anti-nuclear bunkers with survivors, and so on. Apart from gaining more hosts, the goal was to secure various resources and materials - something no one would expect from their kind. Alas, they were far more pragmatic and calculating than their fictional original.
There was also an attack on a magical settlement. Once again, Harry led it himself. It had to be done flawlessly and no one could have been allowed to escape.
There was a metamorphmagus among these new acquisitions. Harry was curios how the drone was going to turn out. Later on, during full moon, another group hunted down and captured a pack of werewolves. Again, an interesting kind of a host.
As time went, many people kept dying of radiation sickness. Population dropped drastically. This hit merpeople, centaurs, and others as well. On the other hand, dragons and other powerful creatures remained unaffected. Dementors roamed free and fed on people indiscriminately. They ignored the aliens though, almost as if they were invisible to them. That was no great surprise.
Muggle population was in chaos. There were various gangs prowling around, trying to survive at the expanse of others. Some armies were trying to enforce law and order but succeeded only in small areas, if at all.
Goblins were pretty much inactive. They hid from radioactive fallout in caves and dungeons and kept a low profile. Maybe they knew about the new power which was about to conquer Earth. Maybe they simply wanted everybody else to make their moves before making any decisions of their own.
Some wizards learned about the Xenomorph invasion eventually. They didn't found out how smart they were though and considered them just another previously unknown magical creature. As a result, no one made a connection when a large magical settlement which planned to eradicate the creatures in their area was destroyed by a nuclear bomb. They blamed muggles instead and for a while, the conflict between the two was rekindled.
When "Harry's" forces did come out in earnest, it didn't really matter how many people saw them. The world was no longer as interconnected as before. Internet was gone along with everything else. Harry's queens and their hives gained ground and no one ever came to aid people in the conquered areas. However, the conquerors didn't behave as one would expect them to.
There was no pointless killing and while many were used as hosts initially, it was only the old and sick. Later on, only the oldest and dying were used. After all, there was no rational reason to use young people. Moreover, they didn't behave like human occupational force either and they actually didn't need anything from humans (other than hosts).
At this point, Harry was certain that all the goblins around the world knew about the new rulers of the planet. Somehow, he doubted that they were sheltering wizards and working with them on some kind of a biological weapon which would wipe all the hives out. He figured that they wished to be neutral, just like they had been with wizards before (hopefully with less armed conflicts though).
After several years, the situation on Earth more or less stabilized. Harry had to admit that it wouldn't happen so fast without the hives. Every hive was like a nation, with a queen on top of its hierarchical pyramid. Most of these "nations" hosted human population on their territories.
Such people lived in virtual serfdom on one hand but on the other, they paid no taxes, didn't need an army to protect them, and were allowed their own law enforcement and judges to settle their internal affairs. Need for new drones gradually decreased so only exceptional people were being selected to serve as hosts at the end of their lives. Some human settlements even formed a religion around this and perceived it as a form of an ascension.
All in all, real life aliens were quite the opposite from the fiction. Even Harry's original vision was a far cry from how it all turned up in the end. They were more like Formics or Arachnids. Using an analogy from Earth's politics, an apt description would be a perfect communist society.
All the hives formed a global network. It was decentralized but the first queen served as a kind of an unofficial "chairman". Harry's importance gradually decreased and he was relegated to an advisory and auxiliary role. He sometimes worked as an undercover ambassador to humans but he had no influence on the hives. It seemed that the others understood perfectly well that he wasn't one of them.
After much observation and deliberation, goblins chose to establish contact. They and the hives managed something that the humans of the old had found very difficult - peaceful relations without any "goblin rebellions". Once again, Harry doubted that goblins planned some kind of a treachery to become a dominant species themselves.
However, it was the dragons who were the uncontested dominators of the world. With their caretakers gone, they took to the skies and ranged all over the planet. Bearing no love for Harry's brood, they roasted any drones they saw. Sometimes, they even ate them but they preferred game. The queens saw no reason to do anything about this because it was a good natural mechanism for weeding out their population.
Of Voldemort, no one heard again. Maybe all his horcruxes had been destroyed in that first nuclear holocaust. Maybe his visions had no place in the new world. Maybe he possessed a drone and recognized its kind as his own creation - which it partially was. It had to be admitted - Harry had provided the shape but Voldemort had provided the substance.
Many years later:
Harry (in his monstrous form) stepped through the last blast doors in a resistance base. It was eaten through by blood of a sacrificed drone. That may be seen as wasteful but it was actually cheaper and more convenient than using explosives. The drone was injured anyway.
The fighting inside was mostly over. There were a few non-magical humans wielding high-tech weapons combining machine guns and flamethrowers. Only one wizard left. Strangely enough, he didn't apparate away nor did he summon Fiendfyre. Maybe he didn't know how. Maybe it had something to do with a gigantic rocket behind him.
So that was what they had been building. Harry knew that it was something big when their goblin informants brought this resistance cell to their attention but the reality was way grander than his theories.
They had known that there was a black market and that goblins were trading with free humans. The queens (with a little input from Harry) debated the matter and decided to leave them alone. He argued that by eradicating those last few pockets, they would be also extinguishing the last spark of genuine human ingenuity because for the moment, all the best wizards, scientists, and inventors lived outside of their influence. Understanding this was quite a leap for the queens but not as big as some might think.
Moreover, goblins needed access to better wizards, which the "resistance" loaned to them in exchange for materials and other resources they required.
And so they made a deal. Goblins continued their black market activities and the hives looked the other way. In exchange they reported any trades which suggested something bigger than usual.
And so Harry found himself in a large underground complex. It looked old but with recent renovations. Maybe some clandestine research facility which had escaped their search?
All the opposition was broken. There was a sole survivor who looked like a chief engineer. He tried to kill himself but the drones prevented him from that. He was brought to Harry.
Being old and having consumed many brains, Harry didn't achieve a perfect read when his inner jaw penetrated the man's skull. It was mostly a series of pieces. However, he did manage to focus his search on the project the resistance had been working on. Together with findings of drones searching the complex, he managed to understand the whole picture.
They had planned to send people to another star system and found a colony there. A colony of free people to preserve their culture. The engineer didn't know much about the planet though. The means of getting there though, that was his department.
There were two rockets, each with its own silo. The plan was to launch both of them at the same time. They carried two different payloads of similar weights which were supposed to connect at the orbit.
One was an interstellar engine. Its nuclear reactor didn't allow for such a big acceleration as a chemical one but it could add up to a much greater velocity over sufficient time.
The other part was an ark. Drones who secured the silo didn't enter it and waited for Harry. The consumed memories revealed that it contained two dozen of adults in stasis, thousands of embryos, and supplies and equipment to start a colony (including artificial wombs). Magic had been used to increase the ark's capacity but the engineer didn't know much about that.
Personal inspection revealed further details. There were three separate containers with magically enlarged space inside them in the ark, self-contained and shielded so their magic wouldn't interfere with the ship's systems. Nothing was done about the weight because the mechanics of spells like Locomotor wouldn't work in getting something to orbit. Enchantments on the magical containers were only temporary. It seemed it's only purpose was to make the design of the ark more compact and thus make it easier to get it out of the atmosphere.
Once in space, the containers were meant to be extended out (thus making the exterior as big as the interior) and remain non-magical for the rest of the trip. As for landing, the three modules were supposed to descend separately but they didn't have their own propulsion. They did have grid fins for manoeuvring and various parachutes though. The idea was for the ark to detach from the interstellar engine and de-accelerate. Once in atmosphere, the modules would eject while the ark itself would burn. The engine was meant to be left at the orbit for future generations.
Before that, however, another part of the ship was supposed to detach, land on the planet, and survey the landing area. There was a small lander for that purpose and it could, if still attached to the ship, also serve as its cockpit. There were two extra stasis pods in the central part of the ark for the pilots who were supposed to do this task and safeguard the success of the mission should anything unexpected happen. The room with the pods had computer terminals in them which could also be used to control the ship. Harry checked the names on the pods and remembered that two pilots with such name-tags on their uniforms were killed during the battle. Luckily, the flight was automatic.
They had to act quickly. Regardless of what they wanted to do, they had to do it before the space enlargement enchantments wore out. Harry returned to a staging area which had been set near the first rocket by the drones in the meantime. Using a strange communication device which didn't resemble anything human-made and which utilised even stranger language and protocol, he added his latest findings to a report filed by the drones already.
While the queens were deliberating, he hurried about finding additional information. The most important thing was to find out more about the ship's destination which, as stated before, was yet another thing which the chief engineer had known little about. It was a planet similar to Earth which could theoretically support life. However, Harry doubted that it had breathable atmosphere and drinkable water.
Luckily, more information wasn't hidden behind heavy encryption. The planet had been discovered shortly before the nuclear war. Spectral analysis revealed its similarity to Earth. After the rise of the hives and forming of the resistance, magical technologies were used to find out more. Similar size and gravity, water, and atmosphere containing enough nitrogen and some oxygen (which possibly suggested presence of primitive algae). Obviously, the air and water couldn't be used "as is" but that was no problem.
All the navigation data was already in the ship's computer. That simplified things a lot. They were basically prepared to go.
Another interesting detail was that the stasis chambers could be briefly opened without waking the person inside up. That, along with their dossiers, gave Harry an idea.
The queens finished their deliberation. They agreed with Harry to finish the mission. His reasoning was that the people in the ark were the pinnacle of human intellect and the frozen embryos were also carefully selected. No matter how stable and peaceful the "ordinary" human population was, their subservience to the hive queens went hand in hand with a loss of certain edginess so typical for certain humans - humans like Harry himself or the resistance. The fact that the queens had yet to colonise Mars or Venus while some underground resistance constructed an interstellar colony ship proved that point perfectly.
The adult people in the ark could be used to hatch new drones and the embryos could become a foundation of a new human colony protected and guided by a new hive. To that end, Harry went through the ship's database and erased anything about what had happened after the nuclear war.
A few goblins arrived to take a look at the installation they had helped to find. They weren't allowed inside the ships though.
As the preparations continued, Harry contemplated what his own role in the endeavour was going to be. This question went hand in hand with another: What was his role on this planet lately? The hives didn't need him any more. Moreover, he was getting old and so his usefulness decreased even further. Unfortunately, this very fact also negated any possibility of him actively participating in the upcoming adventure.
As he wandered through the ark module during his pondering, he passed a reflective surface. Driven by a sudden idea, he looked around and saw that there were no drones in vicinity. He phased to his human form, for the first time in many years. It was more difficult than he remembered but he managed in the end.
A blurred reflection of an old naked man stared back at him. His physical state was even worse than he originally thought. There was only one course of action left for him.
He reverted back to a monster. Once again, he was met with certain difficulty. It wasn't as if the process was more complicated than before but it simply took him longer.
He issued appropriate instructions to drones working on preparations. He didn't even think about saying goodbye to the first queen. Such a thing would be quite sentimental, human even.
The adult colonists were implanted with a larvae - they were never going to wake up. A warrior drone took the copilot's pod. It was selected for its above average intelligence. Final countdown started.
Then it was Harry's turn. He turned to his human form and was implanted. It was quite an unpleasant experience.
The ships lifted off, both at the same time, just as planned. Connection went automatically without a hitch. Harry extended the container modules. The ship was completely non-magical from that moment.
He was starting to feel discomfort from the larvae. It was high time to get inside his pod. He still waited till the main engine was engaged. Only when he was satisfied he gave himself a "stasis injection" a closed himself in his pod.
While his body slept, a small part of his mind which still exhibited a low level of activity dreamt. In his dream, Harry connected with the larvae he carried and started to share his memories with it.
Many years later according to the ship's time and several centuries according to Earth's, the ship assumed orbit around the destination planet. The pilots' pods opened and Harry's larvae burst out of his body. It had most of his memories but it would be ridiculous to say that it was his reincarnation or that it shared his personality. It felt no connection when it looked back at his body and felt no revulsion as it feasted on his flesh.
The adult drone walked to a terminal in the meantime and activated it as instructed back on Earth. There were automatic checks under way and scans of the atmosphere and surface. The drone didn't understand completely what it saw but it resembled a pattern it had been trained to look for.
After initial scans were complete, the entire ship went automatically to a lower orbit and started new scans. Each step of the procedure was carried out as planned until the ark alone descended to an orbit from which the final landing procedures were supposed to begin.
Both the drone and Harry's larvae went to the cockpit. Strictly speaking, they could open all the other pods and take the larvae with them but it had been decided against it back on Earth. It was better not to put all eggs in one basket.
The ship's computer found a perfect spot to land all four craft and start a colony. All they had to do was to get there with the lander and signal back. There were some contingencies for a case the lander didn't make it, of course. Originally, those had involved waking the others up but Harry disabled that before his implantation. The ship was simply going to trigger the descend automatically and try to drop the containers without any guidance from the lander.
Once in the lander, the drone performed the few mechanical actions necessary for decoupling. The craft implicitly operated in auto-pilot mode. It was clear that if something went wrong, there would be nothing they would be able to do. Such was the price for excluding any humans from participating in the mission.
They "strapped themselves in" (or rather fooled the system to think that both pilots were safely secured in their seats) and the drone pushed a button confirming readiness to launch and a countdown appeared. They had to wait for a window. A bizarre trivia was that the drone could actually read the numbers and understand that it denoted the time left. Harry's larvae spent this time by getting its bearing and sorting out Harry's memories. Its brain wasn't fully developed yet though so they didn't made much sense yet.
Finally, the time for launch came. Nothing grand happened in the beginning though. Just a low-powered decouple which could be barely heard inside the cabin. A new countdown appeared. After some time, when the lander was clear enough, it turned and used RCS to get more distance. Only then did it fire its engine and started to decelerate.
The ride down was rough but well within the capabilities of the autopilot. They touched down on the planet's surface and signalled the fact back to the ship. The signal for initiating the second (and final) phase of the landing wasn't sent yet though.
The drone opened the door and, ignoring a warning about the atmosphere being unbreathable, ran out to scout. Harry's larvae watched as it ran around in a spiral pattern. Some time later, they started to loose contact with the ship due to its low angle above horizon.
All in all, there was nothing of interest around them. They were surrounded by wasteland and, as they knew already, that wasteland stretched over the entire planet. If there had been any human scientists with them, they would have started taking samples to see if there were any primitive algae but the two Xenomorphs didn't care much about that.
When the ark rose above the horizon again, Harry's larvae sent a signal. The ark acknowledged the signal and before it made another orbit, it started its descent into the atmosphere.
They noticed a cluster of burning shards on the sky first. Those were the remains of the ark. None of them reached the surface, all of them burned in the air.
Three fireballs came afterwards. They slowed down though and stopped burning. Their parachutes started to open. One by one, the containers touched down in the selected area though the one with the passengers ended up some distance away.
When the adult drone reached it, the stasis pods were deactivated already but, due to Harry's changes on them, the people inside didn't wake up. Before too long, their larvae started to hatch and feast on their bodies. The other two containers were left unopened for the time being.
Days (which were almost twice as long as Earth ones) passed and the hatchlings grew. Harry's one had a small head start in that. They searched the area thoroughly and scouted the broader surroundings. Other than water (frozen and mixed with other substances), they didn't find anything.
Harry's drone grew smarter and smarter until it could process Harry's legacy. It didn't make the other drones not to consider it as one of them (unlike in Harry's case). Another interesting trivia was that while the adult drone was de-facto in charge, it didn't fully assume leadership. It acted more like a guide and a caretaker. Maybe it was because the drone wasn't part of the new brood - it was part of one of the Earth's hives sent there to assist in creation of a new one.
They opened the container with supplies and started building a base. They wanted to start growing first human embryos as soon as possible. By the time they were done with basics, "Harry's drone" grew to adulthood and started showing symptoms of pseudo-magical abilities similar to those Harry had commanded when in his monstrous form. It also proved much smarter than the Earth drone.
It was then when the old drone provided its last service to the new hive - it challenged the budding leader. While the older drone seemed to have an advantage thanks to being older and thus more developed, it ended up being a rather one sided fight. Armed with an ability to read its opponent's mind while keeping its own hidden, the younger drone won and became a new leader and a future queen.
Years passed and first generation of human colonists grew. The colony didn't become what the authors of the idea had hoped it would become - a think tank of independent and bright humans. Then again, maybe the project would fail entirely without the supervision provided by the drones.
Strangely enough, Harry's drone never wondered about what was happening back on Earth and for the moment, they had no way of finding out. As for the other drones, Earth was a concept as distant for them as for their human charges. It didn't matter much - their responsibility was the planet they were on at the moment.
As said, the first generation of humans wasn't spectacular at all. Being born from artificial wombs and not having parents affected them significantly. Their social behaviour resembled that of the drones taking care of them. They accepted the breeding program outlined to them in instructional videos without question.
Following generations had a little bit more spark in them though. They started to wonder what happened to this mystical Earth they were taught about, how had their parents gotten there, and who were their guardians. Seeing that the drones ran outside with no protection while they themselves needed spacesuits, they came to a theory that the drones were native to the planet and took care of the "human ark" out of curiosity and "goodness of their hearts".
This theory was somewhat contradicted by their knowledge that the drones hatched out of old people. They had not seen it yet but they knew about it from their guardians. This was confirmed when the first generation reached an age when health complications became more and more common. One by one, they allowed themselves to be put in narcosis from which they never woke again. For the first time since its formation, the hive grew.
Younger colonists debated what this obvious link between them and the drones meant. For some reason, their species were compatible so maybe the supposed aliens were actually from Earth. Moreover, new drones looked just like the older ones which meant that the older ones were hatched from humans as well. All of that raised many questions but in the end, the colonists never knew any other life than that under the protection of their guardians. Some even proposed that they were genetically engineered to help them on this barren and inhospitable world. That begged a question why there wasn't anything about them on the data drives brought from Earth.
As time went, less drones were hatched. Like on Earth before, only extraordinary people were chosen when they grew old. At the same time, healthcare for the remaining elderly was limited and many old people with failing health chose euthanasia to conserve resources. Hence, not being chosen wasn't considered a good thing. Eventually, being chosen started to be seen as an ascension, just like in some places on Earth.
On first glance, the colony wasn't better in any way to previous hive-nations. The ruling ideology was pure communism. Everybody had to work, everybody was assigned same quarters according to family size, everybody ate the same food in mess halls together. The only recognition for rising above average was being chosen to become a host.
And yet, this setting didn't stifle human ingenuity as much as it had been expected. Maybe it was because of the challenges of living on another planet. There was a constant stream of problems to solve and not just for their survival but for improvement of their lives there. The final goal was to terraform the planet, after all. It was the holy grail of all their toiling and way beyond their league at the moment.
Magic reappeared in time but not on the scale it was expected by the founders of the project. None of the embryos donated by magical parents grew into people with magical aptitude. It seemed that there was more to it than DNA. Fortunately, a few of the descendants of such "squibs" displayed hints of magic several generations later.
As there were no teachers of wizardry, the queen taught all the children (using telepathy to convey instructions). As with all things related to aliens, it was considered a great honour. The drones built a special temple for that and human engineers connected it to the colony's ventilation system. They couldn't install air filters directly in the temple because of the EM interference from practising magic.
The books and wands brought from Earth proved to be useless soon enough. Maybe it was because of the planet, maybe it was due to people there having a different mindset. Conventional curriculum had to be dropped and the queen started to teach more basic powers such as telepathy (which the students already needed to be able to communicate with their teacher) and telekinesis.
For all this time, drones kept searching the planet, using the orbital scans as a guide. One day, they discovered a cave system with liquid water. A laboratory was constructed some distance away from the city and samples were brought there. Human scientists discovered some primitive algae in them. Perhaps it was something they could use in the terraforming process one day?
Alas, such thoughts were premature. They still had a long road ahead and the queen suspected that Earth was going make contact with them before that (unless something terrible had happened there). But that is another story.