Precursors are a staple of a great many Sci Fi and Fantasy settings. While precursors come in many different varieties, the defining aspect is that they existed in the time before a setting's contemporary civilization.
Recursive Precursors occur when the concept of precursors is applied recursively; such beings served a similar role to precursors as they do to contemporary civilizations. The odds are surprisingly high that precursors to these precursors had even had another race that served as their own precursors, and so on, forming a long line of ancient civilizations.
Of course, having a long series of precursor races carries some disturbing implications. Beyond the fact that precursors existed in the time before the setting's present civilizations, another important aspect of precursors is that they are no longer around. Perhaps it is In Life's Nature to Destroy Itself. Perhaps they were wiped out by their creations. Bonus points if those creations went on to become precursors to another young civilization. Maybe they were wiped out by an unrelated group of Precursor Killers. Or maybe they were Sealed In Some Sort Of Can. Less pessimistically, it's possible they've just ascended to a higher plane of existence, died out for mundane reasons, or simply left the immediate area for whatever reason.
Naturally, this is a Sub-Trope of Precursors. When Creating Life is involved, this trope is highly compatible with Recursive Creators, but is otherwise not related to other "Recursive Tropes" such as Recursive Reality and Recursive Fanfiction.
- In Gall Force: Eternal Story, the Solnoids are the precursors of humanity; in Gall Force: Stardust War it's also revealed that the Solnoids also have precursors. Finally, in Gall Force: New Era, it's revealed that due to a Stable Time Loop, all the races in the story are each other's precursors.
- Lyrical Nanoha has Al-Hazard, which served as the precursors of the Ancient Belka empire after Al-hazard destroyed itself, which in turn served as the precursors of the current setting after Ancient Belka destroyed itself.
- In the Pony POV Series:
- The first set of precursors was the Centaur Empire, the greatest empire of it's day and was on it's way to being Benevolent Precursors. They were also rather nice to the ponies before they were uplifted and became sapient. Unfortunately, Lord Tirek is the Sole Survivor of their species because killed them all and is most certainly an example of Abusive Precursors.
- The G1 ponies were this to the Golden Age civilization (depicted in Tales), and where the ones to wipe out the monsters, witches, and other horrors reeking havoc on the world. The Paradise Ponies continued to safeguard the Golden Age civilizations due to the Rainbow of Light making them immortal until Discord damaged it and they eventually passed on of natural causes.
- The Golden Age was this, being the most advanced civilization on Equus has ever gotten. Unfortunately, the civilization was destroyed in the magical equal of a nuclear holocaust when the wish spell they tried to make a utopia with. Also Benevolent Precursors, as said wish spell created the Lost Age, which was indeed a utopia until things went horribly wrong and many members of it did everything they could to minimize the damage of the apocalypse and preserve their advances for the civilizations to come.
- In the Star Wars Expanded Universe, there are multiple races of precursors, starting with the Celestials, who created the hyperdrive triangle which makes galactic civilization possible. After them came the Rakata, who built a massive Empire, created the basis for all hyperdrives, and left behind things such as The Star Forge. Contemporary with them were the Gree, who among other accomplishments built the infrastructure that makes Coruscant's planet-wide city possible before withdrawing to a handful of worlds where they survived until the 'present' of the series.
- In Carl Sagan's novel Contact, when the humans make First Contact the Sufficiently Advanced Aliens who sent them the blueprints for the device used to access the setting's Portal Network, they reveal that they were not the original creators of said Portal Network. It is also revealed that whatever being(s) did create the Portal Network had their own Precursor(s) the creator(s) of the universe - who may be God � left a message in the form of the numerical sequence of pi.
- David Brin's Uplift series. The original precursors, the Progenitors, existed a billion years ago. They uplifted non-sapient races into intelligent beings. The races they created themselves uplifted more species, and the process has continued to the present day.
- In Larry Niven's Known Space universe, there are two sets of precursors. First there were the Thrintun (AKA "Slavers"), who seeded the galaxy with the ingredients of life so it would grow and evolve into unique delicacies for them to eat (being hypnotic slavers, they were defeated by the Tnuctipun in the inevitable Turned Against Their Masters, and they took all sentient life with them. Talk about bad parenting). Then there were the Pak, a race of more recent aliens with three life stages (child, breeder, Protector) only sapient in the third stage, and programmed to be homicidal to anything that could conceivably threaten their descendants (mutations were not recognized). Earth was a Lost Colony of them who couldn't advance to Protector stage when their supply of tree-of-life root ran out due to a lack of thallium in Earth's soil.
- In Strata, archaeology has uncovered several layers of precursors that died off for various reasons (including one race that died of shock on discovering that they had precursors). At the end of the book, the heroine meets a representative of the first ever precursors, who reveals that they are actually the only precursors, and they planted all the archaeological evidence of other precursors to give the universe more of a sense of history.
- In Planet of Adventure, the humans of Tschai are broken down into groups based on which alien species they are associated with. Each group regards their masters as the "real" precursors, although an outsider can tell that this is ultimately not true.
- Used in The Gray Prince by Jack Vance: each of the pre-human colonist species claim they are the true owners of Koryphon and have the right to expel all others. It turns out that none of the intelligent species on the planet are indigenous: the true natives are the orcish cannibals who by now exist only in fenced-in preserves.
- In The Book of Lost Tales, the pagan Anglo-Saxon mariner Eriol knows of 'the gods' (the Valar) but an Elf has to tell him about Ilúvatar, "who was not of the Gods, but made them."
- In Andrei Livadny's The History of the Galaxy books, initially has Absent Aliens for about half of the thousand year timespan of the setting. Then one extinct and three extant aliens races are discovered whose heyday was three million years ago (humans have actually surpassed them in certain areas such as hyperdrives and cybernetics). Then two more races are discovered whose heyday was billions of years ago (they survive by the first being a race of Energy Beings who helped the other one Ascend to a Higher Plane of Existence). They also talk about a race of Abusive Precursors who nearly wiped them out and may yet show up in future stories. There are creatures that everyone calls Forerunners, but they are not sentient and appear to be a swarm of Planet Eaters. What takes the cake is an Energy Being that some call "God" who may actually be the unintentional creator of all biological life in the galaxy and is the actual creator of the Forerunners (the ones eating planets have programming errors).
- In Gene Wolfe's epic The Urth of the New Sun, the Hierogrammates were created by humanity in an earlier cycle of the Universe. They now forge humanity of the current Universe.
"Your race and ours are, perhaps, no more than each other's reproductive mechanisms."
- Robert E. Howard's Kull series, set in an age long before his Conan the Barbarian tales, occurs in the "fading, degenerate" land of Valusia, a place "living mostly in dreams of bygone glory, but still a mighty land and the greatest of the Seven Empires", and considered so ancient that the "hills of Atlantis and Mu were isles of the sea when Valusia was young."
- Ken Scholes' The Psalms of Isaak has several layers of precursors. The direct precursors to the novels' modern civilization was the empire of the Wizard Kings, who conquered the world out from under the hands of the Weeping Czars. Both groups were preceded by the Younger Gods, who were in turn preceded by the Elder Gods, though these were so ancient that little knowledge remains of them other than the name.
- In the Perry Rhodan series, a million years ago the Barkonids settled the galaxy as their planet was shot out of it. New colonies weren't given a lot of technology to prevent them from becoming decadent, which let most of them to become low tech. Over 50,000 years age the 'First Mankind', the Lemurians, settled the galaxy again, but they were wiped away in an interstellar war and fled to Andromeda galaxy. Then at least 20,000 thousand years ago we get the Akonids, who spread out but become really isolationist after a colonial war of independence with the Arkonids, who are currently becoming decadent, the next step will probably be humanity.
- Babylon 5: Lorien and the rest of his kind were this to the other First Ones, like the Vorlons and the Shadows before moving beyond the Rim. Humans and other species of the Alliance are to take over the cycle for the next group of species to evolve, before they too move beyond the rim.
- Battlestar Galactica: The People of Kobol were precursors to the 13 Colonies and the People of the 13 Colonies are our Precursors, but there was presumably no one before them unless you count whatever "It" is that doesn't like being called "God" and the Head People.
- In Doctor Who, we have the Eternals, some of which were apparently the seldom mentioned gods of Gallifrey; precursors to the Time Lords who are themselves (sometimes) cited as the reason for there being so many races of Human Aliens, Rubber-Forehead Aliens, and Humanoid Aliens in the Whoniverse.
- In Red Dwarf all known life in the universe originated on Earth, with humans acting as precursors to countless other races, who in turn acted as this to even more sentient creatures.
- In the Stargate-verse, the Goa'uld were originally thought to be the ones who had built the Stargate network, come to Earth to find slaves, and built the Pyramids to land their spaceships. SG-1 quickly discovers that while the Goa'uld were indeed the ones on Earth thousands of years ago, the Stargates were actually built by their precursors, the Ancients, millions of years ago. Stargate Universe revealed that the Ancients had found signs of their own precursors (or God), but the series ended before they could be revealed.
- The Star Trek Expanded Universe is full of these. There's all the uberpowerful noncorporeal life, and the ancient humanoid preservers, and a hundred or so other ancient powerful empires. The unexpanded universe has more than a few already, though not quite as many, and often a bit vague on timing.
- In Greek Mythology the first major figures are Gaia and Oranos, whose children were the Titans, many monsters, and the Gold race of men who died out by not reproducing. Then Cronos, the leader of the Titans, castrated Oranos and overthrew him, then Cronos' kids overthrew him (yeah, they've kind of got a children killing their parents theme here). Also Zeus created the Silver race of men, but they were too warlike and he had to destroy them, so Prometheus made the Bronze race who were our ancestors. Then the Olympians wiped them out with a flood, but Prometheus' son Deucalion and his wife Pyrrha survived by floating in a chest. Zeus took pity on them and told them to throw stones behind them. The stones thrown by Deucalion became men, and the stones thrown by Pyrrha became women.
- Norse Mythology is kind of similar, with Odin and his brothers killing the primeval giant Ymir, making the world out of his body, and instituting the rule of the Aesir.
- In Warhammer 40,000, Eldar are a borderline example of a Precursor Race, in which case their creators, the Old Ones, would qualify as well, alongside the Necrontyr/Necrons, and the C'tan Star Gods.
- Forgotten Realms elves dominated Faerun before they torn both continent and their civilizations apart in Crown Wars, which left them weakened and gradually displaced by human expansion, all the while Dwarven and Giant kingdoms still fought each other. But the Elves in turn took the world from Dragons' claws. That's where we switch from merely mythical era to the Time Abyss of Creator Races about whom little is known: Dragons fought giants after knocking birdlike Aearee out of Toril's sky... Aearee in turn spread when Batrachi got themselves extinct, before their time there were Sarrukh and Fey, and so on. And before that was "Time of the Rauth" — prehistorical era when something was going on too, but what is completely lost by now.
- Eberron has a long history of being ruled by demons, then dragons, then giants, then goblinoids (in Khorvaire), then finally the common races. Some of them are still around to some extent, from the Dragons of Argonessen to the Demon Wastes to whatever is happening in the depths of Khyber.
- Traveller Gurps Alien Races 3 discusses this as an optional alternative for lore about The Ancients. However the normal canon does not discuss this much.
- In Homeworld, the ancient Hiigarans left their hyperspace core to be discovered by their descendents 3000 years later. But the Ancient Hiigarans never built the core, they found it. It was made by a still older race known only as the Progenitors, who, according to legend, are said to have originated from beyond the galaxy.
- The Mass Effect universe has a bunch of these. Of course, due to the Law of Conservation of Detail, only two of these races�the billion-or-so-year-old mechanical Reapers and the 50,000 year old Protheans, respectively the first and last in the line of recursive precursors, are relevant to the plot.
- Javik reveals that the precursors to the Protheans were the Issuanon, whose ruins on Ilos were where the Prothean first discovered Mass Effect technology, much like Humans had from the Prothean ruins on Mars.
- Towards the end, it is even considered that the Citadel Races might become the precursors for the next generation of galactic species.
- In the Extended Cut, one of the options at the end is Refusal — revolted by the Catalyst and its options for ending the war, Shepard refuses to fire the Crucible. The united fleets of the galaxy are vanquished by the Reapers and all sapient, spacefaring life in the galaxy is harvested (again). However, the epilogue shows one of Liara's time capsules (which she mentioned compiling earlier in the game) being discovered and explaining to an unknown species the cycle of extinction, the Reapers, the Crucible, and the story of Shepard's war. In the final scene, an alien speaker explains to a child how, through the help of those who came before them, they were able to defeat the threat of the Reapers.
- And just to top everything above, in the Extended Cut of ME3, the Catalyst reveals that the Reapers had their own precursors, who also created him as means to solve the organic-synthetic conflict. His monologue implies that said precursors looked more or less like a organic version of the Reapers and were (not entirely voluntarily) harvested into the very first Reaper (believed to be Harbinger in the lore).
- In the "Leviathan" DLC, Shepard can meet some of the eponymous species, which created the Catalyst (and by proxy, the Reapers). Uncounted millions of years later they're still bitter about it, but after seeing so many cycles go by, they've become too scared of the Reapers to aid the species. Shepard's goal becomes convincing them to aid the current cycle and stand up to the Reapers. They're still very much Abusive Precursors, but they understand that the Reapers can not be allowed to go unchecked anymore.
- The Dead Space games have an almost identical overarching scenario: The Brethren Moons scattered Markers throughout the galaxy. When a civilization finds one, the artifact will compel them into worshiping it or attempting to replicate it (since it's a source of unlimited energy). The Marker triggers a Necromorph outbreak which eventually culminates with Convergence, the creation, of a new Brethren Moon out of countless Necromorphs. This is what happened to the natives of Tau Volantis, it's currently happening to humanity, and it's probably why space is dead.
- Halo's Forerunners had the preceding species precursors, who were rumored to have exceeded technology and become transentient. By the time of the Flood invasion, many believed the precursors were legend, unaware that they had defeated the precursors millennia before and the Flood was their revenge. Literally, as a number of precursors broke themselves down into a dust that, millions of years later, would become the Flood.
- In the Star Control series, the first Precursors we know of is the race that left behind the massive battleship that the Ur-Quan use, who themselves Turned Against their Dnyarri slavemasters, who themselves had killed their own precursors, the Sentient Milieu. The reason for the original Precursors not being around anymore was eventually revealed in (the often-ignored) Star Control III ; they were wiped out by an Even More Advanced race, possibly their own Recursive Precursors.
- The Freespace series has some in-universe speculation on this. The Ancients were the precursors to the modern-day Terrans and Vasudans, but they were wiped out by a total enigma of an advanced species called the Shivans, who are now attacking the Terrans and Vasudans. One character speculates that the Shivans have been around for a really long time, and exterminating any civilization that evolves to a certain point like they did the Ancients, though there is no direct evidence that this is the case. Some Word of God statements about the never-made third game implied that the Shivans themselves are an engineered species, so that would be another Precursor race who did the engineering.
- The aliens from Escape Velocity Nova known only as Those Who Came Before merged with the universe millennia before humanity achieved space travel. The epilogues to four of the storylines mention that humanity followed in their footsteps several thousand years later, becoming precursors to another alien race.
- In Shadow Realms, the world of Embra has seen multiple civilizations rise to glory before annihilating themselves in various kinds of magical apocalypse (something which is made dangerously easy by Embra's magic-rich environment). The fact that the Radiant Empires didn't go down the same road is considered quite an achievement - but it didn't stop them getting attacked by an Outside-Context Problem.
- The Master of Orion series has this in its backstory. An ancient precursor civilisation sent out various groups through an unstable wormhole when it's star was found to be close to going supernova. The descendants of some of those became the eponymous Orions, the main precursors for the first two games. By the third game the Antarans, originally enemies of the Orions who returned in the events of the second game and canonically won, have accidentally wiped out most of their civilisation and effectively become a third tier of precursors.