Xeelee Sequence

The Xeelee Sequence, by Stephen Baxter, is a sprawling series of novels and short stories all set within the same universe.

In the far future, mankind expands out into a hostile universe, filled with intelligent species as weirdly varied as they are ruthless. Above them all, however, are the top dogs of the universe: the Xeelee, the god-like de facto rulers of the universe. The various novels in the "sequence" follow various threads, such as Earth being invaded and occupied by bizarre aliens, or a hopeless war between mankind and the Xeelee, along with various other stories concerning humanity's place in a relatively bleak universe.

Overall, the Sequence is a loosely connected series, covering literally billions of years of history with later stories expanding the scope to include literally the entire history of the universe, from beginning to end. The main connecting thread throughout all the novels are the Xeelee's enduring presence and influence on the history of the universe and mankind. The series has a definite chronology, but the novels and short stories were published in Anachronic Order. However, all of them can be read as individual stand-alone stories.

Novels in the Xeelee Sequence:

Raft: An accident strands a group of humans in a universe where gravity is much stronger.
Timelike Infinity
Flux
Ring
Vacuum Diagrams (short story collection)
Reality Dust (novella)
Riding The Rock (novella)
Mayflower II (novella)
Starfall (novella)
The Destiny's Children sub-series
- Coalescent
- Exultant: During mankind's Third Expansion, Pirius the Greenship pilot and his friends pull off a bold tactic to capture a Xeelee and its Nightfighter. Returning to the past, he and his younger self are not welcomed as heroes but rather tried as criminals and learn more about the dark side of their government than they ever wanted to.
- Transcendent
- Resplendent (short story collection)

Tropes used in Xeelee Sequence include:

Abusing the Kardashev Scale For Fun and Profit: The Xeelee have absolute mastery over the entirety of all baryonic matter in universe. Entire galactic clusters are just bricks to these guys.
- Future humans make it to Type III and try to attack the Xeelee by shooting a whole neutron star at them like a bullet. The Xeelee brush this off as though it were insignificant.
- There's also the Photino Birds, creatures of dark matter against whom the Xeelee fight a multi-billion year existential war and lose, who have absolute mastery over all the dark matter in the universe (which outmasses regular baryonic matter by about 9 to 1).
Aliens Are Bastards: Played straight with some species. Averted (more or less) with the Xeelee, who go out of their way to prevent extinction of other sentient lifeforms, even humanity, which repeatedly attacked them.
- Also averted with the Silver Ghosts, who are much less aggressive than humanity (except the Black Ghost) but unfortunately end up in the path of the Third Expansion.
Anti-Villain: The Xeelee have such a bizarre morality due to their Technological Singularity and obscene age that it's impossible to say if they're even truly malevolent towards races they dislike.
Ace Pilot: Jim Bolder, hence his being entrusted with a Xeelee nightfighter by the Qax, with bad results. For them.
Beyond the Impossible: By the time of Exultant humanity has converted almost the entirety of the Milky Way into an industrial war machine with which they are engaging in a multi-millenial pan-galactic campaign against the Xeelee. Still, the Xeelee view this as roughly the equivalent of an especially persistent cockroach infestation, and think of humanity as little more than pond life.
- Celestial bodies up to and including entire galaxies used as projectiles? Megastructures millions of light years across? Handguns that can destroy stars? Aliens altering the value of Planck's constant simply in order to build a faster computer? Stephen Baxter was rocking this trope before it was mainstream.
- In a different vein, the Interim Coalition of Governance is the Imperium from Warhammer 40,000...only (arguably) worse.
Big Damn Villains: The Qax are tricked into fulfilling this role at the end of the final story in Vacuum Diagrams, distracting the photino birds long enough for the last of humanity to escape through the Ring.
Big Dumb Object: The novels feature an object called "Bolder's Ring", built by the titular aliens; it's constructed out of the remains of galaxies (later revealed to be cause of the real life "Great Attactor"[1]) and is essentially a black hole that has been stretched into a one-dimensional loop millions of light years in length. It's eventually revealed to be an escape route for the Xeelee from the Universe, by means of tearing a hole in spacetime through the middle of the ring via the unimaginably strong gravitational forces created through its rotation.
- Also, the "Sugar Lump" - a perfect cube the size of a small moon, which appears to serve no purpose whatsoever. Later is revealed to be one of many identical devices which sent the Xeelee back in time to essentially create themselves using a Stable Time Loop.
Bond Villain Stupidity: The Qax could have saved themselves a lot of trouble if they had simply exterminated humanity.
Child Soldiers: Most of the main characters in Exultant.
Colony Drop: There's the extreme colony drop option where a Neutron Star is accelerated to high fraction of light speed and smashed into Bolder's Ring (see Big Dumb Object above).
Cool Ship: Xeelee nightfighters, which can travel at near-lightspeed even before they fire up their hyperdrive, by flapping wings made of folded space-time.
Crapsack World: Millions of years of humanity in a massive Hopeless War of attrition against the Xeelee who are also fighting a race of dark matter beings who want to render the universe unfit for baryonic life (like humanity). They lose. First the humans, than the Xeelee.
- Well, at least the Xeelee not only managed to get the hell out of the doomed Universe, but also provided means for at least the remnants of humanity to escape. While some refugees from our Universe ended up in one that was practically unfit for human life, this wasn't any of the known evacuation groups, so there is at least some hope for the humanity...
Did Not Do the Research: A lot of it, despite Baxter's attempt at doing hard science fiction. Black holes with hair, for example, or control of causally disconnected structures... and other scattered inconsistencies of what the setting's technologies are stated to be able to do, and what they actually do.
Forever War: The Xeelee are nearly immortal, and humanity quickly proves itself a race of consummate survivors. They don't like each other. Do the math. But even that pales before the Xeelee-Photino war.
Genius Bruiser: The tribelike mannerisms of the Boneys from Raft hide minds well-versed in orbital mechanics to rival trained scientists.
Guile Hero / Magnificent Bastard: Jim Bolder.
Higher-Tech Species: The Xeelee are an extreme example. Despite being "only" this trope (because their universe-shattering technology is recognizable as such), they could absolutely run rings around quite a few examples of Sufficiently Advanced Aliens from other works.
Hoist By Their Own Petard / Nice Job Fixing It, Villain: Thank you so much for discharging the star-disrupting gun right next to your own sun, Qax!
Humans Are Warriors: In spades, at least once the Interim Coalition of Governance takes over. The titular alien Xeelee outclass them in pretty much every sphere of technology, but the Fantastic Racism of mankind's "Third Expansion" era doesn't let a little thing like that stand in the way of galactic conquest. A line in Exultant expresses humanity's fighting strategy; something like: "To the Xeelee, we were little more than rats - so that's what we became. Tenacious, relentless, swarming; fighting an interstellar war with teeth and nails".
Human Subspecies: Especially so in '"Flux: Humans have been modified to microscopic lifeforms to live within a Neutron Star.
I'm a Humanitarian: The big secret of the Boneys in Raft.
Insufficiently Advanced Alien: The Hive Mind fish aliens known as Squeem conquer Earth at one point despite being no more intelligent and not much older than humans - but they lucked out on finding technology left over from the sufficiently advanced Xeelee.
Intangible Man: Michael Poole after the Anti-Xeelee
Lensman Arms Race: The Xeelee use cosmic strings to build a Kerr metric known as "Bolder's Ring" in order to escape into another universe. The Ring is so massive that it's gravity well is pulling in galaxies from all directions towards it at high speed. The Xeelee's antagonists the Photino Birds one up on this by meticulously arranging galaxies around the Ring in just the right pattern to form a gravitational resonance that will shake the Ring apart.
No Dead Body Poops: Implied aversion in Raft. One character sees "a shape hanging from rope" and "a pool of something brown and thick" beneath it.
Poor Communication Kills: The most epically enormous example ever. Humans start their second war with Xeelee because they believe that the Ring is intended to wreck the Universe. No, it's created as the only way for any form of baryonic life to escape extinction. Photino birds who is the cause of this extinction in turn, are so alien, that they most likely do not even realise that they are genociding multiple sentient species by making the Universe more comfortable for themselves.
Reality Warper: The Snowmen technology used to protect Earth in The Siege of Earth (in Resplendent) seems to at least border on this.
Scry vs. Scry: Humanity fights a War against the Xeelee over the Milky Way Galaxy where both sides can send information backwards in time using FTL. In practice, neither side can ever get an advantage. This goes on for tens of thousands of years.
Shadow Archetype: The Anti-Xeelee is an aversion-the name actually refers to the fact it travels backwards in time, like some anti-particles are thought to do. The Photino Birds, on the other hand...
Space Whale: The Spline are giant living armored spaceships that evolved from alien whales. They live off interstellar gas and other species use them as transports and warships. In one case, the entire Qax race, which consist of cell-like vortices in any fluid (ocean, air, gas giant, star, space-time...), is transported off its homeworld when the sun goes nova.
Stable Time Loop: Xeelee sent themselves back in time to supercharge their own development.
Starfish Aliens: Pretty much every single race in the series. There's almost nothing remotely human-like, aside from humanity's descendants.
Sufficiently Advanced Aliens: The Xeelee are really not this trope, even though their actual power far exceeds many other examples that are. This is simply because their godlike technology is still recognizable as such and uses comprehensible interfaces, if not comprehensible principles; they're a hyper-extreme example of Higher-Tech Species instead. However, their creation/creator the Anti-Xeelee definitely is sufficiently advanced, in a Deus Est Machina sort of way.
Third Person Person: Quid from Raft.
Time Abyss: The traitorous collaborators with alien overlords who conquered earth who were given eternal life: "My name is Luru Parz. I was born in the year AD 5279, as humans once counted time. Now I have lived so long that such dates have no meaning. We have lost the years, lost them in orders of magnitude."
Unperson: The alien Qax attempt to do this to the entire history of humankind, in a project know as the "Extirpation", in order to make humans more docile slaves.
Wave Motion Gun: The Xeelee starbreakers, which shoot focused gravity waves that can tear apart stars or cause them to go nova, certainly qualify. By the time of Exultant, humanity also uses guns which fire magnetic monopoles and later black holes.
Who Wants to Live Forever?