First of all: This is completely non-profit, I write all this for fun, and I am essentially putting together the best parts of different well-known franchises together, to make a crossover multiverse with some changes made to the original stuff (such as the Star Wars galaxy.)

BRACE YOURSELVES FOR THE ULTIMATE SCIENCE FANTASY CROSSOVER!!!

Just a note for the audience: Of course, this crossover does not cover EVERY sci-fi universe and magic system. In fact, it only covers the ones I'm familiar with.

So prepare your butts for this epic campaign of universal domination!

STARHAMMER 50K: THE FIRST WAVE

But first I'd like to credit all the existing content from various creators and authors, that I'm blending together to make this multiverse:

The realms of Starhammer 50k are spread over a vast plane of existence that is at least 4 galaxies and 5 million light years wide (the Milky Way galaxy, the Andromeda galaxy, the Triangulum galaxy, and the Double Helix galaxy.)

It combines lore, worldbuilding, characters, timelines, and content from dozens of fictional universes and franchises, the big three being Star Wars, Warhammer and Halo, but also including many others, such as Undertale, Dungeons and Dragons, Transformers, RWBY, Avatar: The Last Airbender, Starbound, Battletech, Genshin Impact, Thrones and Bones, EXO (a book by Fonda Lee,) N.E.R.D.S, (by Michael Buckley,) Ranger's Apprentice Book 1, (by John Flanagan,) even Doctor Who!

Sorry, Star Trek. I just never got interested in the Federation when I had other favorites in my childhood and puberty like the Galactic Republic, the Covenant and the Imperium.

Now for the intro:

It is a dark time for the Galactic Republic. For a thousand years, war has raged across space and time, and it shows no signs of stopping. The Enemy Within and the Enemy Without continue to grow in strength and number, while the Republic's people are more divided than ever. Every day, the forces of tyranny grow stronger, and the Arsenal of Democracy is beginning to lose its sheer dominance.

Among the manifold enemies of democracy are the Covenant, an alliance of religious alien zealots, the genocidal superorganism which mortals call the Mind Flayer, the teeming hordes of the Orks and their numerous subspecies, the Flood, a parasite that perfected the capabilities of necromancy, the Confederacy of Independent Systems, a separatist movement from the Republic which wages war using a droid army, the Creatures of Grimm, a race of demons who seek to obliterate all other sapient beings, the Daleks, a tyrannical group of alien bigots with cybernetic bodies, and many, many others.

But even in these dark times, there is still hope. As long as there is evil... good will rise up against it. After all, freedom is the right of all sentient beings. It certainly isn't free... but it's definitely worth fighting for.

"I went to war with murderers, thieves, with slavers and dealers, the parasites who preyed on human weakness. That weakness was a feeding ground that stretched beyond the infinite. The evil it fed would never end. So I decided, neither would my war."

-Lieutenant Frank Castle, "the Punisher," veteran Space Marine and urban vigilante on Coruscant

And YES, Space Marines and Jedi coexist and fight side by side in this version of the Galactic Republic that I put into the story. BURN THE HERETIC!