How do I keep my sci-fi from being too HFY?

My sci-fi setting is built around the concept of a massive two-way between an expansionist /pol/tier human military dictatorship and its roughly two-dozen brutally conquered vassal species, against a loose alliance of little over forty libertarian-leaning species, while a handful of extremely isolationist and nomadic species remain neutral. Most of he alliance and humanity's vassal species have had FTL tech for millennia, but humanity barely left its solar system five centuries ago. The problem is, I can't think of a non-HFY way for humanity to have expanded that quickly, without some kind of unrealistic asspull. Do you guys have any ideas?

>*A massive two-way war

Sorry for the typo.

some kind of sneaky third-party alien race is giving humanity a boost behind the scenes for their own shadowy agenda

What sort of sci-fi are we talking? Hard, soft, space opera, green-skinned slave girls?

You could always use the standard:
>extremely rare element is required for FTL
>there was a shitload of it in Sol's asteroid belt or Kuiper belt

This. Or, there's something protecting humans and the space around them from anything else that wants in.
Or, they found a tomb world conveniently very close to earth, and sucked up all the sweet, sweet technology.

Blitzkrieg ×100.
A combination of Humanities natural ingenuity and Unexpected(and irresponsibly) assault on the Alien species.
For Example: The Galaxy had been at Peace for a large time. The libertarian leanings of many of Humanities neighbors led them to ignore a growing threat. So WHAT if the humans were building up their forces to massive levels? After all, don't a free species have the right to guard themselves? Especially Humanity, with the recent discovery of extremely rare metals in the Belt. Metals that contain the secret to unmatched FTL. They salivate over trade possibilities why the humans build up, their rhetoric growing increasingly aggressive. Then a conflict erupts among a few alien species. Some of the bigger ones. The humans of course, claim no involvement(they are agitating for both sides). The Major powers pull their forces to other fronts. Then, Humanitie's moment comes.
(Red Alert!)
(Red Alert!)
Unexpectedly and without warning, Humanities fleets breach space major world's near the border. Caught at their moorings, the Alien fleets are demolished and in a matwtwr if hours, all forces posing an immediate threat are in full route. Within a week or two Humanity has almost doubled the space under their control. The Opening Offensive is a masterpiece of warfare. Nobody expected it. Those who did were shouted down as fearmongers. The Mastermind behind it all? Admiral(and Duke) Heinrich Shwarzenhoff, Duke of New Bayern(One of the Empires first colony worlds).
Thus were the opening stages to the Great War, and the Alliance has yet to recover fully from the blows.

People who hate on HFY are faggots.

The sci-fi is squishy, no space magic, magic nanobnanobots, or anything like that, the only thing soft about it is the inter-spaceship combat, which I'm handwaving as being similar to terrestrial naval battles, because it allows for boarding actions, devastating broadsides, and I like it that way. I'm also ignoring scale to some extent, the conflict is confined to a few hundred thousand stars. Also, limiting FTL to a specific rare resource alongside the obscene amount of power needed is a good idea.

Hmm, the third species is a good idea. There's a long-gone Precursor species that terraformed and seeded hundreds of planets in the galaxy with bacteria designed to grow into humanoid lifeforms, as in two arms, two legs, one head, etc, which is the reason most species in the galaxy are bipedal. A nearby Tomb World is a good idea that meshes well with the setting, but it still seems hand-wavey, because there's no reason there wouldn't be sufficient Tomb Worlds in alliance space, considering the Precursors at their height had a galaxy-spanning empire.

Hmm, I like this idea. Maybe the reason humanity expanded so quickly is their rigid societal cohesion and the fact that their society is essentially one massive war machine? I could see that.

Don't worry, there's plenty of HFY, the other species also have kickass attributes and things they do better than every other species. I just want to be able to set up the war scenario without blatant and unrealistic handwaving. Humanity's hat is that they're around the top 20% of species in regards to average intelligence because they instituted an extreme eugenics program a millennia ago, and that they're aggressive enough to wage total war, but not aggressive enough they keep themselves in the stone age.

Oh yeah, OP here, in case some of you are retarded, this was me. Sorry for forgetting to mention that.

(Continuing)
....The First Great War ended with a whimper rather than a bang. Humanity WOULD win, this much the Band of 40 (as they came to be known) knew. They had been too unprepared, too unready. But they fought on. Heinrich(by now known as the Voidwolf for his many stunning victories) saw his genius match up against an ever more desperate and United enemy. Humanity's shock and awe offensive was running out if steam after nearly 10-years of conflict(they expected at most a five year conflict). They were winning, but hadn't WON. So, Heinrich, under pressure from home, and with the end of the war in sight, launched the war's final offensive.
The Gloriana Campaign.
The Gloriana system formed the solid core of the Band's defensive system line. It had to fall for Humanity to reach the core systems of the Band's most important member species. For Months the fighting waged, bitter desperate. Victory after victory he won, and Gloriana neared his grasp. Close. So close. He just needed more ships and men. He messaged Earth that with reinforcements, the war would end within a Year.
But there were none to give. Humanity had at last been exhausted. The war hadnt meant to last this long. Conquered world's needed garrisons. Conquered space needed ships. Heinrich knew what he had too do.
Gathering his forces, Heinrich struck for Gloriana.
He nearly had it. *Damn* he nearly had it.
The Battle of Gloriana was the largest of the war. Every member of the Band sent ships.
Humanity's finest warrior against the might of 40 species.
It was not to be.
Despite a 4-1 kill ratio, The Voidwolf was driven back. 3 days later, he radioed Earth.
The War could go no further. It must end now, whilst Humanity still held their foes by The throats. 1 month after the Battle of Gloriana, the Treaty of Gloriana was signed. Humanity was left in control of a Great portion of the galaxy, though Gliding and its surrounding systems remained free The peace was signed. But it pleased none

(Gliding)
I meant Gloriana

Aliens are all recovering from a previous galactic war.

Humanity is very united, while the aliens are so loosely collated that they squabbled amoungst themselves when they could have united against the threat.

Humanity used innovative tactics that other aliens weren't taking into possibility (boarding torpedoes?)

Aliens are recovering from a galactic super plague that just got quarantined.

HFY is just autistic because there is already A LOT of stories where humans are being badasses, special and win against aliens so the idea that humans are being dominated by aliens in fiction is just some weird persecution complex.
HFY is just a stupid label and self-proclaimed "HFY stories" tend to be too on the nose, with mary-sue humans and too much focus on masturnating about how humans are being better.
Also sometimes HFYfags can be annoying by hating any stories where humans are not superior to all the aliens or if the humans are been presented in any negative light,etc... and that the authors or fans of these stories must somehow hate their species.
You don't need to put the label "HFY" on any story where humans are badass and the best, and there is nothing wrong with writing a story where humans are not the best or even special and especially heroic.

Humanity managed to surprise the powers at the start of the war with sabotage or an unannounced first strike on shipyards and anchorages destroying large parts of their fleets before the war got underway.

Humanity commited a LOT of Galactic warcrimes. How much they're actually warcrimes to our human culture is up to you.

Aliens with their libertarianism weren't able to create a cohesive enough force, with many ships operating independently and harassing the humans, but the humans always wining large battles and planetary invasions.

As for the the conquered species living in the new human territory. What about a
"Honour Terran" system?(gotta get them Nazi references in). The Aliens living in the territories can, (usually through military service and proven loyalty to the cause) be recognized as an "Honour Terran." What that amounts to us up to you. It would certainly set them above those without such a status. Preferential treatment, actually decent living conditions etc. Not sure how racist your Humans are, but it could be interesting. Humanity's main problem in the first Great War was manpower and overextension. Having loyal Sepoys you can count on to not stab you in the back would be useful. Of course, those less inclined to join their conquerors are gonna have issues with that.

Basically my idea submitted above. I just added more fluff.
Mass Fucking Space Blitzkrieg.
With the compulsory honourable German Admiral.

>Rare materials.
I think of civilization developments kind of like a Civ game. If you get lucky on turns 1-20 with your resource placement, you snowball. If you get lucky with resource spawning 2/3 of the way through (get all the oil) you can recover from being behind if nobody notices for a while.

Here's my question, how did humanity become a dictatorial engine of war? I'd assume that it could be done if humanity immediately had a war on first contact (bad first impressions last a long time). This has a problem though, if humanity had a contact war too early, we might not live long enough to get our rare minerals mined and expand to full power. We'd be trapped in our small status forever. If we had time to catch up, it might not make as much sense for us to be violently xenophobic. I'd expect a system that finds the ability to use FTL more than anyone else would be renowned as explorers, colonizers, and scientists rather than as vicious soldiers.

Ignore this if you posted a reason in the thread already, I can't tell if this one is you or some rando.

Not OP but he mentioned a rigorous eugenics program a millenia prior, while Humanity has only had FTL for 500 years. This means that 1000 years ago there was a totalitarian government that managed to control enough of humanity to make such a change.

I'm guessing based off that that the one world government that united Humanity just happened to be totalitarian in bent rather than individualistic. Granted there could have been regime changes since then, but humans kept going back to some kind of unified totalitarian machine. That machine just so happened to point to war when the opportunity presented itself

>Here's my question, how did humanity become a dictatorial engine of war?
Our own psyche favours this. Historically we have been more at war than at peace and freedom is something very new and already dissapeared in all but name.
>We'd be trapped in our small status forever. If we had time to catch up, it might not make as much sense for us to be violently xenophobic.
They're aliens user. Their appearance and behaviour would be disgusting for humans due to their strangeness. Think like the aversion that many humans have towards snakes and multiply it million of times.
>I'd expect a system that finds the ability to use FTL more than anyone else would be renowned as explorers, colonizers, and scientists rather than as vicious soldiers.
Our intellect evolved because we were vicious hunters, from hunters to soldiers is just a step

>Our own psyche favors this.
You have a point, but what I'm getting at we're not very good at getting everyone onboard one idea unless there is something big enough to scare the whole lot of us. We can become a bunch of dictatorships, but everyone will favor their own dictator and we won't get unified. If there is an alien out there to be scared of, it's already too late for us to catch up with them, unless some other factor is at play.

Fear of a greater threat

Maybe tomb worlds are absurdly dangerous and humans were the only ones who were willing to expend the lives necessary to penetrate the planet's defenses, or lucky enough to not set off the planet's big guns/self destruct nonsense. Perhaps the humans are, through a fluke almost as unlikely as life itself, a near match for the precursors, so their tomb worlds accept human colonists, even defending them.

Why are the precursors no longer the big dick in the local neighborhood?

Maybe they figured out immortality, and the first immortal dictator is the current one? He'd probably basically just be a giant supercomputer mr house style. Iron grip on everything using his near omnipresence and super enhanced intelligence.

Oh, hollow out the moon, fill it with big ass computers, create an artificial super cooling atmosphere, make an ultimate council which has it's fingers in damn near everything, and has had for a millennia or so.

This.
It reminds me of a theory I once heard my grandpa spew out when I was a kid when I might have asked something about aliens.
''If there's something out there, they better hope we don't notice, because there are few things as prevalent in humanity than a common hatred.''

Only use humans.

There you go user.

user if you want classic WW2 style naval actions, you could take the Stars Without Number approach and say that quantum ECM prevents long range guided munitions from working properly

>Sir, de Germans are marchings to Baris :DDDD
>Dey shall not bass :DDD
>Oh fugg :DDD

Characterisation and mortality is the key.
Read the original Starship Troopers book or watch something like Generation Kill. If the party likes random NPC you characterise them then murder the shit out of them and make it the player's fault. I make a habit of stating 90% of NPCs in my games to make them effectively mortal a-la the radiant NPC engine in Oblivion.

e.g..
>game I'm running at the moment is some low-fantasy Chinese civil war deal
>players trekking across a country in the middle of a huge insurrection
>throw in and old man and grandson NPCs as Mr Exposition/Worldbuilding and a bit of direction
>made sure to stat them
>rebels force the party to smuggle some crates into the next city they're coming to
>rebel leader sends a couple of disguised agents along to guard it
>players debate the pros and cons of the two main factions and if they should align with one of them
>decide if they murder the agents and throw them and the cargo in a ditch then they still haven't taken a side
>players jump the two agents in an elaborate "cart wheel came off" plan
>rebels have loads of gunpowder weapons
>one player lights a bunch of old-fashioned firebombs the last agent has on a bandolier
>boom
>decide to have this ruin their cart since the guy was on it at the time
>chuckle to myself
>"oh fuck what was in the crates?"
>it was gunpowder and more bombs
>hadn't even factored that in
>roll more dice
>realise the two NPCs were hiding on the cart too
>roll more dice
And that's how you make players feel genuinely guilty for killing children through their own recklessness

OP here, humanity went through a massive solar system wide war decades after colonizing Mars and the Moon. The war went on in a brutal stalemate two decades before one side employed weapons of mass destruction, causing the other side to retaliate in kind, and the vast majority of the species was killed by nuclear fire and hellish plagues. Nearly a century went by before a faction of disparate neo-fascists, most of them latino and asian, and military remnants, allied by necessity and shared ideology, managed to unify the far-flung asteroid settlements, isolated earthly survivors, and the remaining cities on Mars and the Moon under a single military government. After the war among the species, most humans came to believe humanity needed to unite and prepare to survive the possibility of another war, and the faction capitalizing on this, managed to take power.