Does the Commonality cloy a bit? Or do you want to get to know the 'opposition' so as better to defeat them? The Venu are the 'bad guys' of this setting, being a cruel and oppressive civilisation that are the diametric opposite of what the Commonality stands for and strives for. Of course, there are opportunities there too...
The Introduction explains how the Venu can be seen as what Earth's civilisation might have become had they chosen a different path. They left very early on, maybe eight thousand years ago or more and have been treading their own road ever since. The present Venu aren't that old, because they destroyed themselves fighting one another - this Venu civilisation is at most fifteen hundred years old, having built itself up on the ruins of more ancient ones. They are a rich and complex society, and this book attempts to present them - warts and all - with the aim of providing resources for adventuring in Venu space, creating meaningful Venu NPCs as adversaries (or allies?), and maybe even playing the odd Venu character.
Chapter 2: History and Prehistory goes into detail on the real history of the Venu. Most if not all of the present-day Venu don't know about it, as that apocalyptic war fifteen hundred years ago wiped out most of what went before, and the time since has been one of oppression, false news, and lies masquerading as the truth. It all began with the first ship using stasis technology to leave Earth. Heading for the Orion Nebula, their intended destination turned out to be unsuitable for habitation but fortunately they found a nearby world on which to settle. It wasn't ideal and after some struggles a major terraforming plan was put into action. They'd been there almost a thousand years before a message from Earth arrived... by then they'd almost forgotten where they came from and it was a decided shock to hear a planet on the other side of the galaxy claimed to be their origin. Even more, technology on Earth had advanced far more than theirs, and the information transmitted enabled the recipients to gain ascendancy over the rest of the planet, leading to a three thousand year long golden age. Then a second message came, reflecting further changes on Earth and again sending the Venu into a tailspin. Some accepted what they were told, others refuted it, nobody would agree to differ and it all ended in tears... and apocalyptic war!
From the shattered remnants left by that war arose the immortal God-Emperor Venu. Forty generations later, his followers the Pure hold true to his Tech Commandments, building their world as directed. And then the Commonality came, a real cat amongst the pigeons. The God-Emperor broke a long silence to issue more edicts, the New Pronoucements, and now leads his people in war against the Commonality seeking to defeat their 'lies' and embrace something called the Radiant Darkness, a relgion seemingly cooked up for the purpose, having consolidated his hold on surrounding worlds and colonies seeded before all the unpleasantness happened and contact lost.
Scene set, we then begin to find out about the Venu people themselves in the next chapter. They seem to be a surprisingly uniform bunch, tending to dark hair and skin, but more worryingly, in their behaviour too. Society is very conformist (at least in part out of fear) and hierarchical. Technology is prolific yet subject to myriad rules and restrictions, for example travel permits are required even to move about your own city let alone travel to another planet.
Chapter 4: The Venu Empire starts by looking at the political hierarchy with the God-Emperor at the top assisted by fifteen Lords Countenant who each head one of the government departments or commissariats. They deal with nearly every aspect of life - it's quite hard to do anything at all without their influence being felt. The majority of the population are the Pure, the obedient masses. There is great fear and hatred of so-called Abominations; mutants in other words. With loads of detail to bulk this out, there are also plot seeds scattered throughout. Chapter 5 continues this background information by looking at the Dark Radiance... but just what is this? It hovers somewhere between a religion and a personality cult, centred of course on the God-Emperor himself. It's of particular interest because it appears to confer certain powers on those it mutates. Those mutated by Dark Radiance are not ostracised like other mutants, rather they are regarded as favoured or blessed. Chapter 6 then explores Venu technology, something they are ambivalent about. The society is anti-intellectual, yet they realise that they need tech to survive and prosper. This results in most people having little understanding of the technology that they use, often with disasterous results. The chapter contains an extensive catalogue of equipment.
Moving on, Chapter 7: Starships and Space Travel reveals that Venu space technology is somewhat behind that of the Commonality. The classes and deployment of military vessels are discussed here, as well as civilian ships - there are even a few deckplans. Ships sorted, we go on in Chapter 8 to explore Venu Space, beginning with the homeworld, Venu Prime and including detailed instructions for designing your own worlds. There are plenty of examples of solar systems in Venu space to visit as well.
After what seems to be quite a massive information dump - fascinating stuff, it's taken me ages to read and I've enjoyed every word! - we move on to more game-mechanical stuff with Chapter 9: Creating Venu Characters. Whether or not you are willing to let your players be Venu depends on the game you want to run, but it's useful to be able to create detailed antagonists anyway. There are a range of different cultures, genotypes and careers to choose from. Then it's time to look at Chapter 9: Venu Adversaries, which provides an array of ready-made 'bad guys' to throw in the party's path. There's a bestiary here too.
Finally, Chapter 11: Venu Campaigns looks at the vast variety of things you can do in Venu space now that you know about it. Perhaps the party are Venu, and options range from Imperial intrigue to trying to discover what Dark Radiance actually is, or perhaps formenting a rebellion against a repressive society. On the other hand they might be Commonality - spying, perhaps, or out to wreak havoc amongst their enemy. There are plenty of ideas thrown out in a sentence or two... but like most everything else in this book, you will need to put in some work to actually use it in your game.
A fantastic overview of a major player in galactic space, which really gives a good feel for and understanding of what to the Commonality are bogey men. There's too much that isn't for player eyes to make it a useful book for the whole group - even if they are playing Venu - so be prepared to explain a lot! Definitely a useful addition exploring this whole new region of space and its inhabitants, an addition to the setting capable of being used in many differnt ways.