An Elseworlds series written and illustrated by John Byrne, Superman & Batman: Generations is built upon one central conceit: the complete and total Aversion of Comic Book Time. Generations consists of three different series:
Generations I (1999) focuses primarily on Superman and Batman, beginning with their first meeting in 1939, with each subsequent chapter jumping ahead ten years to show later events in their lives as well as the lives of their children, grandchildren, and so forth.
Generations II (2001) details events that take place between the chapters of the previous series, as well as giving larger roles to other DC heroes like Wonder Woman, The Flash, and Green Lantern. The series starts in 1942, with each subsequent chapter jumping ahead by 11 years.
Generations III (2003-2004) crafts an epic story by bringing in Jack Kirby's New Gods and focusing on Darkseid's plan to conquer the universe (or, at least, get those pesky human superheroes out of the way first). The story starts in 1925 and each subsequent chapter jumps ahead 100 years, before reaching its ultimate conclusion that retcons itself out of existence.
The Silver Age of Comic Books: Book 2 (1959-1969), which shows some of Superman and Batman's sillier adventures, before getting darker with the death of Dick Grayson in 1969.
The Bronze Age of Comic Books: The first part of Book 3 (1979), following the previous spoiler, with the marriage of Bruce Jr. and Kara Kent, and ending with Lex Luthor's murder of the Kent family.
The Dark Age of Comic Books: The second half of Book 3 (1989), where the heroes get angrier and more violent thanks to the deaths of their families, ending when they acknowledge their downward slide and take steps to correct it.
Alternate Timeline: Of an alternate timeline. The basis of Generations III is that an alternate future from the one shown at the end of the first series is created, but by the end the timeline is wiped out and replaced with the proper one shown in the first one.
And the Adventure Continues: Generations I ends with Superman and Batman and Lana Lang going off to see if there's anywhere else in the universe that needs heroes; the caption at the bottom even reads "Never The End".
And Your Little Dog Too: Not satisfied with killing Superman's family, Ultra-Humanite kills off his friends and their families too, including Jimmy Olsen, Lucy Lane, Perry White Jr., and a dozen others.
Anti-Hero: Batman III (Bruce Wayne Jr.), owing primarily to his unresolved rage over his wife's murder.
Apocalypse How: In Generations III, Luthor-Metallo unleashes a "blackout bomb" that acts as a Class 1, reducing the world to the level of Jack Kirby's Kamandi stories. Made worse by the fact that all pre-bomb technology remains deactivated for 300 years, meaning humanity has to start over from scratch.
Arc Words: "Why do I feel like somebody just stepped on my grave?"
Art Shift: Byrne does his best to imitate the art style of the era, such as the original Seigel and Schuster look for 1939 Superman, or a style reminescent of the DC Animated Universe for 1999 Batman.
Ascended Fangirl: Hyena, one of the villains of Gotham City in the 1980s, modeled herself after the greats of Batman's rogues gallery.
Asian Babymama: Mei-Lai, first the wife of Joel Kent and the mother of his son Clark. When Joel dies, Mei-Lai marries Bruce Wayne Jr., and is more successful in helping him break out of the grim mindset Kara's death brought on him than she was with Joel.
Aside Glance: Superman winks at the reader at the end of the 1942 chapter, just like he did back in the day.
Back in the Saddle: The 1999 chapter has Bruce Wayne gladly taking up the mantle of Batman once more, after entrusting his "new and improved" Legion of Shadows to Bruce Jr. Superman also qualifies to an extent, since he spent the last decade in the Phantom Zone, though once he gets out he leaves Earth to explore the galaxy.
Badass Normal: Any of the Batman Family up to Clark Wayne, but special mention has to go to Johnathan Kent, who goes after Ultra-Humanite with a shotgun to help Clark and Bruce (and is actually the one responsible for Ultra being parapalegic).
President Harold "Hal" Jordan strangely hits upon this insight, given that his normal DC Universe counterpart as Green Lantern turns on the Green Lantern Corps after the destruction of Coast City and becomes Parallax.
Big Good: After Ra's al-Ghul's death, Bruce Wayne takes over his organization and turns it good, simply by turning the "front" organizations legit. He passes it on to Bruce Jr. so he can go back to being Batman.
Blessed with Suck: The formula that the Ultra-Humanite/Lex Luthor gave Joel Kent to restore his Kryptonian powers ended up killing him after a few hours, despite his mentor's original claims of the contrary. Which, of course, was what Ultra/Lex was hoping that Joel would believe.
Later, however, it was revealed that Ultra/Lex had come up with a formula that did restore Kryptonian powers without killing whoever drank it, as Superman and his grandson Clark Wayne (Knight-Wing) had found out.
Brain Uploading: In Generations III, Lex Luthor uploads his brain into the computer banks of the Superman Museum, granting him access to the whole planet's computer network.
Cain and Abel: Joel Kent is the Cain, having been stripped of his hereditary Kryptonian powers while in the womb and mistakenly thinking he's The Unfavorite; Kara is the Abel. They even play this up to the point where Joel kills Kara.
Call Forward: In the first chapter, Bruce and Julie look at a poster for the Flying Graysons, and Bruce says he heard that their son is a real "Boy Wonder".
In the 1929 chapter, Bruce (as Robin) improvises a boomerang out of a piece of scrap metal, foreshadowing the Batarang. And in the 1919 chapter, young Bruce makes a costume from random parts (including a fox mask) and calls himself the Flying Fox; as Superboy helpfully thinks to himself, the flying fox is another type of bat.
In Generations II, Kara tells BJ about her Supergirl wig, saying that it won't come off unless she removes it on purpose or she dies. This is of course a reference to Generations I, where Kara's wig falls off her lifeless body after Joel murders her.
Canon Discontinuity: Generations III writes itself out of existence: when the heroes destroy Darkseid once and for all, reality "shatters". The last page shows Kal, Bruce, and Lana in space as per the ending of Generations I, with Kal and Bruce commenting that something feels off and hoping that they haven't forgotten anything important.
Combat by Champion: In the 1959 chapter, a group of aliens come to Earth looking for a great champion to help them. Both Mr. Mxyzptlk and Bat-Mite think their hero is best, but to ensure a fair contest, each of them has to test the other's champion.
Continuity Nod: Clark Wayne's twin daughters, Lois and Lara, call themselves Supergirl Red and Supergirl Blue respectively. This is a nod to the infamous "Superman Blue and Superman Red" imaginary story which later was used in a different form in the 1990s Superman stories.
Contrived Coincidence: When Ultra-Humanite's rocket blew up, his body was damaged beyond repair while his brain was intact, while Lex Luthor's brain was badly damaged but his body was intact. This allowed Ultra's robot minions to put his brain in Lex's body.
Another one gets a lampshade later on: In the 1929 story, a young Bruce throws together a costume using random scraps and calls himself the Flying Fox, which Superboy (who knows about the future) mentally observes is a type of bat.
Crazy-Prepared: One of Batman's hallmarks would appear in a story centered around him and his family. In particular, Bruce Jr. develops machines that let him fight off the Justice League single-handedly.
Dead Guy Junior: Wonder Woman's daughter is named Stephanie (nickname Stevie) after her father Steve Trevor, who was killed while flying a mission over Vietnam.
Death of the Hypotenuse: Lois is killed by Luthor in 1979, and some time in the intervening millenium the now-immortal Lana Lang found Superman and they became a couple.
Decoy Getaway: Played for tragedy: Joker sets a trap that kills Batman II (Dick Grayson); Robin II (Bruce Wayne Jr.) switches costumes in secret to maintain the illusion that Batman is immortal.
Deliberate Values Dissonance: Reflecting both real-life and comic book attitudes. For example, in the 1939 chapter, Superman and The Bat-Man are willing to kill if need be, and Lois Lane eagerly talks about how cigarettes are part of her complete breakfast.
Depower: Gold Kryptonite, as in Silver Age Superman comics. Lex Luthor uses it on Joel Kent in utero, robbing him of powers forever. He does the same to Superman later on using Gold K cufflinks. In Generations III, Supergirl uses it on herself on purpose.
Diabolus ex Machina: Lara Wayne exposes herself to Gold Kryptonite so she can age normally and be with the man she loves. As she's doing this, he gets mortally wounded in a battle far away, and she arrives just in time to helplessly watch him die with the knowledge that her powers would have let her save him.
Draft Dodging: In the 1969 chapter, both Joel Kent and Bruce Wayne Jr. refuse to get deferments, Joel because he wants to prove himself, B.J. because he doesn't think it's fair. After Dick is killed by the Joker, B.J. does accept the deferment so he can become Batman.
Dress Hits Floor: A superhero version. Kara grabs BJ the night before their wedding and flies him up into the sky. Then her empty costume comes fluttering down...
Dropped a Bridge on Him: The Recap Episode of Generations III shows that several characters died over the course of the series, we just never heard about them until now The list includes Hal Jordan, Clark and Lois Wayne, OMAC, and Lex Luthor.
EMP: Metallo (Lex Luthor) unleashes one in his first battle in 2008, which shuts down Cyborg. He uses an even bigger one in Generations III that brings about The End of the World as We Know It.
The Empath: Wonder Woman's daughter Stephanie Trevor (Wonder Girl) shares an empathic link with Kara Kent (Supergirl) that allows her to sense whatever pain Kara is feeling.
Era-Specific Personality: The characters are written to suit the setting of each chapter (e.g. the heroes are hard-nosed vigilantes in the 1939 chapter, take wacky hijinks in stride in the 1959 chapter, etc).
Evil Cripple: The Ultra-Humanite, from the time Jonathan Kent crippled him until he had a body swap with Lex Luthor.
Evil Plan: Joker's plan to finally kill Batman, which involves escaping prison in secret and posing as a copycat criminal called Joker Junior, buying a certain building in Gotham and installing an elaborate death trap, and then getting Batman to go there at which point the trap is sprung.
Everyone Calls Him Barkeep: The identity of Mrs. Bruce Wayne was never clarified, and any time her face was shown she was either in Halloween make-up or a very old woman.
Expy: The Justice League of America started out as the children and sidekicks of the Justice Society banding together, pretty much making them this universe's version of the Teen Titans.
Fashions Never Change: Lampshaded and played straight. When Superman accidentally ends up in the 19th century, he simply dons the shirt and slacks of his Clark Kent suit and dirties himself up with road dust, after thinking to himself that mid-20th century fashions aren't exactly in vogue around here.
To a lesser extent, Alan Scott uses his Green Lantern Ring to stave off the effects of old age, allowing him to fight crime for four decades before finally retiring and passing the torch to Kyle Rayner.
Hal Jordan also does the same when he becomes Green Lantern.
Getting Too Old For This: Batman thinks this word-for-word when dealing with Mr. Mxyzptlk in 1959. Alan Scott also goes through this, mainly because Hal Jordan declined to take up the Ring, forcing Alan to stay on until Kyle Rayner entered the picture.
Gambit Roulette: The Ultra-Humanite-in-Luthor's plan, as follows: De-power Superman's son, become the boy's mentor while instilling a hatred for the Kents, pose as Lois' doctor so he can get close enough to kill her, give Joel powers so he can kill his sister BEFORE the treatment kills him, jump into the future, and rely upon pre-set plans to kill off all of Superman's friends and relations while he goes on a wild goose chase looking for a Luthor who isn't there. All this so he can steal Superman's body and powers.
Generations III: Mrs. Wayne tells Bruce and BJ that they aren't really father and son and asks them not to investigate any further, all as part of an elaborate scheme to get BJ to use the Lazarus Pit and become Robin again and thereby making up for the fact that she never allowed BJ to be Dick's partner. Her final message even ends with a self-aware "So...just how well do I know my boys?"
Generational Saga: Kind of the whole point. Going from Bruce Wayne's Batman and Superman to Dick Grayson's Batman to BJ's Batman and Supergirl and back to Bruce Wayne's Batman and Superman. Even more present in Generations II with the expansion of focus from the story of the Wayne and Kent families to the greater DCU and the history of the Green Lanterns, Wonder Women, and Flashes.
Ghost Butler: Alfred Pennyworth becomes one after his death in this series, up until he deals with the ghost of Dick Grayson tormenting a very old and frail Joker.
GPS Evidence: Spoofed in the 1929 chapter. Superboy and Robin examine the crate that contained Lex Luthor's robot for clues, and eventually say that together they can track its origin within 100 square miles. At this point Lois Lane helpfully chimes in with the exact location...which she read off the shipping label.
Grand Theft Me: The Ultra-Humanite's modus operandi. He takes Lex Luthor's body after his own is destroyed in 1939, and he plans on trading up to Superman's.
The Greatest Story Never Told: Lois laments that the story of the century (the marriage of Batman and Superwoman) is right under their noses and they can't do anything about it.
Half-Human Hybrid: Joel and Kara Kent; kids down the line include Quarter Human Hybrids and so forth.
Hand Wave: In the authors' notes for Generations II, Byrne admits that he had Wonder Woman debut one year later than she did in reality (1942 rather than 1941), mainly because he didn't want to wait until another sequel series to bring her into the story.
Happily Adopted: Clark Wayne, Joel's biological son, is given to Bruce Jr. to raise following Joel's death. He finds out some time later after learning Vietnamese, but it never really changes how he feels about BJ.
Help Your Self In The Future: An odd variation comes with Wonder Girl I, an artificial projection of a teenaged Wonder Woman who subs in for the real Diana while she's out of duty due to her pregnancy. Everyone involved (especially Green Arrow) finds this extremely strange and somewhat confusing.
Heroic BSOD: Bruce Wayne Jr. seeing his wife Kara Kent with her heart ripped out.
Heroic Sacrifice: Blackhawk member Chuck stops a smart missile from hitting a military hospital by ramming it with his plane, and then insists on staying in the plane in order to steer it away from the hospital (none of the heroes present can help him for various reasons).
Johnathan Kent warns Thomas and Martha Wayne about their impending murder, but when they learn that this will inspire their son to become one of the world's greatest heroes, they willingly go to their deaths (though they make sure to tell Bruce how much they love him beforehand).
Hero Insurance: In the 1939 chapter, Superman destroys a giant robot from the World's Fair that Ultra-Humanite was controlling. The fair's owner goes to complain, but Superman simply cows him with a glare and leaps off.
I Lied: Pulled with extreme ruthlessness by Lex Luthor: After spending decades convincing Joel Kent that his family hates him, eventually leading to his murdering his younger sister Kara, Lex tells a dying Joel (as a result of a Super Empowering serum Lex gave him) that "I lied, as I always have."
Ra's al-Ghul appears in the story, so of course he deserves a mention. He also discovers that if two people enter the Lazarus Pit at the same time, one will die and his life force will be transferred to the other, making him immortal. He and Bruce Wayne enter and Bruce emerges, restored to his prime. He eventually discovers that he ages one year for every century he lives. Generations III further reveals that that single Pit was permanently changed, conferring this immortality on anyone who bathes in it.
The 2919 chapter shows that Lana Lang became immortal thanks to all the magic and Super Empowering she went through as a young woman.
In the 1949 chapter, Batman dresses as Superman in order to fool Lex Luthor and the Joker, but ends up getting shot. The real Superman vaporized the bullet with heat vision and knocked Batman down with a puff of super breath. Then Robin dropped in in a Superman costume too, getting the villains to expose their Gold Kryptonite so the real Supes can melt the lead safe around it.
Robin II (Bruce Jr.) keeps a copy of the Batsuit microcompressed in his belt (created for them by Barry Allen) in case Batman needs to be in two places at the same time. When Joker manages to kill Dick Grayson, BJ dresses Dick's corpse in the Robin costume and dons his spare Batsuit so nobody discovers that Batman was killed.
Jack Bauer Interrogation Technique: The Bat-Man takes one of Ultra-Humanite's goons on top of a planet display and threatens to let him drop if he doesn't spill his guts. The goon drops, but Superman saves him...and when he realizes what was going on, he proceeds to help Batman by threatening to throw the goon over the edge again, at which point he sings.
Jack the Ripoff: The Hyena, an Original Generation villain from the 1989 chapter who prides herself on imitating Batman's greatest foes; Batman III counters that . Also Joker Junior, who's actually the original Joker in disguise.
Kaiju: Bat-Mite brings to life a movie monster from a billboard in order to "test" Superman. Later Mr. Mxyzptlk creates a spherical monster with flaming tentacles.
Kid from the Future: Superman unwittingly becomes this in Generations III, when an attempt to travel to the 30th century runs into turbulence and sends him back to the 19th, where he runs headlong into Johnathan Kent and Martha Clark as young adults and helps save Martha's life.
Lampshade Hanging: The Reveal mentioned below could be seen as a lampshade on the similarity between the two characters in the original comics.
Last Kiss: A variation in Generations III: Lana Lang, having gone to the future and learned that she won't end up with Clark, asks him for a Last Kiss before her memories are erased. The problem being, this is pre-teen Lana and adult Clark. Many readers were Squicked.
Legacy Character: The other main point of the series. The series covers three Batmen, three Green Lanterns, five Flashes, and many more.
A subversion occurs with Joker Jr.: Joker says he never had kids and he didn't train the new guy, but he certainly approves. It turns out that Junior is just Joker in disguise as part of an Evil Plan to finally kill Batman.
It's not particularly surprising that there are multiple Batmen and Robins; they're Badass Normals who age and eventually die, after all. What is surprising is that Dick Grayson was the second Robin—Bruce Wayne I started out as the first Robin before crafting his image as Batman!
Legacy Immortality: The public at large believes there has only ever been one Batman, though a few characters (particularly the Joker and Doctor Occult) suspect otherwise.
Let Them Die Happy: Joker's Last Request is to know Batman's identity, to "confirm a suspicion" (presumably, that the current Batman isn't the original). Batman denies it, saying "You're the last man on Earth I would ever want to see die happy!"
Loophole Abuse: In the 1964 chapter, Bruce Jr's mother forbids him to partner up with Dick; Kara Kent cheerfully points out that dear old Mom never said anything about working with Supergirl...
Done again by BJ himself in Generations III: After dropping the bomb that BJ isn't Bruce's son, his wife asks him not to investigate any further. BJ immediately sets to work, pointing out that she only addressed that request to Bruce. Later on they learn that this was exactly what Mrs. Wayne intended them to do.
Man of Steel, Woman of Kleenex: Addressed logically. Superman made a pendant that mimics the effects of red sun radiation, temporarily suppressing his powers; Lois wears the pendant while pregnant to keep the super-powered fetus from kicking a hole in her. Inverted by Bruce Jr. and Kara, though no solutions is mentioned in their case.
Meta Origin: In the Generations universe, Alan Scott's Green Lantern powers come from a missing fragment of the central power battery, giving it a common origin with the other GLs even if he didn't originally intend it.
Mind Screw: In Generations III, Metron gives Superman a device and asks him to return it the next time they see each other. Which just so happens to be the 19th century, complete with Past-Metron specifically asking for the device. When Superman expresses his confusion, Scott Free recommends that he not ask too many questions.
Morality Pet: Joel's son by Mei-Lai. Despite having his platoon slaughter a village of non-combatants during the Vietnam War, and murdering his sister by tearing her heart out with his bare hands, Joel genuinely loved his son and wanted to make sure he didn't feel the way he felt growing up. Subverted in that Joel's father never actually lied to him.
Mushroom Samba: Dick Grayson as Batman is tricked into falling down a shaft lined with razor blades that are coated with hallucinogenics, so when he ends up fighting the Joker posing as Joker Junior, things get...really weird.
My God, What Have I Done?: Bruce Wayne Jr. finally snaps out of his "grim and gritty" mindset after he nearly kills Alan Scott in a fight, with Carrie Allen, the current Flash, begging him to stop. He returns to his wife, Mei-Lai, and falls into her arms begging for her help.
My Grandson Myself: The Joker poses as his allegedly-unrelated successor "Joker Junior" by using makeup to hide his age.
My Hero Can Beat Up Your Hero: Robin and Bucky have this kind of attitude going on in the Batman/Captain America crossover. They get over it after swapping heroes for a while.
My Own Grampa: Rather, great grampa. In Generations III, Batman marries Lara Wayne, who is the daughter of Clark Wayne, the adopted son of Bruce Wayne Jr. and the biological son of Joel Kent. So, Bruce Wayne becomes his own great-grandson, albeit not by blood.
In the first chapter, while looking at a poster for the Flyin Graysons, Bruce says their son is supposed to be "something of a boy wonder".
Luthor's classic green and purple Powered Armor and bodysuit from Superfriends are worn by Joel Kent when he crashes his sister's wedding.
In Generations, Kamandi is a descendant of Buddy Blank (OMAC), both characters created by Jack Kirby.
The revelation that Ultra-Humanite had possessed Lex Luthor's body for most of his life might be a nod to the former's history: originally he was Superman's archnemesis and a Mad Scientist near identical to Luthor and Luthor had a full head of hair when one day an art error gave Luthor a bald head as well and DC decided to give the Humanite his Grand Theft Me gimmick so that there wouldn't be two bald scientists fighting Superman.
Named After Somebody Famous: Generations III introduces future Green Lantern Jordan Kelly, who says he was named for "the greatest Green Lantern to ever live".
Never Found the Body: Used pretty much every time someone is "killed". Batman lampshades it both times it happens with the Joker, including in the Captain America crossover.
Nice Job Breaking It, Hero: Ultra-Humanite's robots spent decades restoring Lex Luthor's brain in the hopes of rehabilitating his evil personality. This backfires in the short-term by turning Lex into Generations' version of Metallo, and in the long term in Generations III where he causes The End of the World as We Know It.
Obfuscating Stupidity: Since Superman is involved, of course Clark Kent qualifies. During the World War II portion, he tells Lois that he was declared 4F; his inner monologue reveals that he got a little over-eager and read the eye exam chart in the next room with his X-ray vision.
Offhand Backhand: Bruce Jr. does it to one of Hyena's thugs in the 1986 chapter.
Off on a Technicality: Averted. Everyone involved is more than willing to give Superman the benefit of the doubt when he kills the Ultra-Humanite - it was an accident and self-defense to boot. However, since Ultra had murdered everyone important to Supes, he says he can't be sure he didn't want to kill Ultra and thus asks the court not to make him a special case.
Older than They Look: After Bruce Wayne has his soul fused with Ra's al-Ghul's in the Lazarus Pit, not only is his youth restored to his prime adult age (with a bit of white hair streak), he also ages one year for every one hundred years that passes.
The older Superman gets, the slower he ages.
One-Winged Angel: After spending centuries as a brain in a jar, Luthor manages to get into the Superman Museum and cobbles together a robot body that vaguely resembles his old self.
Painting the Medium: Whenever the subject of a hero disguising his voice comes up, it's represented by an appropriately-shaped Speech Bubble (the pentagonal shield for Superman and a bat for Batman).
Phantom Zone: Batman suggests this as a punishment for Superman after he kills Ultra-Humanite, since he's depowered and wouldn't last a day in normal prison, but solitary confinement would be cruel. He ends up interacting with the real world once in order to save his grandson Clark Wayne's life.
Powers as Programs: Gorilla Grodd figures out a way to use Weather Wizard and Mirror Master's powers to let them steal the powers from Supergirl and Kid Flash. They don't get to put it into practice before the kids break out.
Power Creep, Power Seep: Done intentionally: Superman can't fly in 1939, but Superboy can in 1929 because that's how it was in the original comics (the Superboy stories being written after Supes gained the ability to fly).
Ragnarok-Proofing: Justified: In Generations III, Clark Wayne and his daughters go to the Fortress of Solitude to see if Luthor's technology-nullifying bomb has really worn off. Clark tests the theory by trying to start Pa Kent's car, but makes an off-hand remark about field generators designed to keep all of Superman's exhibits in perfect condition.
Really 700 Years Old: The immortal characters don't look any worse than 40 or 50. Superman eventually has to wear makeup to appear older when he's in his Clark Kent identity.
Exposure to magic has pretty much made Lana Lang immortal, and she's just as beautiful in the 31st Century as she was in the 1920s, despite being alive for nearly a millennium.
Becomes a plot point in regards to Superman's great-granddaughters Lara and Lois, particularly Lara, whose attraction to an alien Green Lantern is hampered because she's Legal Jailbait.
Reed Richards Is Useless: Double subverted. Superman goes into space looking for a cure for cancer, and while he does find some alien medicines that work, they don't work on human beings. Otherwise played laser-straight, as the comic goes through the 20th century with the addition of DC superheroes and supervillains - a extraterrestrial Physical God, representatives of the police force of interstellar civilisation with Imagination-Based Superpower, an envoy from the Lady Land that doesn't appear on maps, mad scientists (Lex Luthor builds a giant robot in 1929) and all the rest - but they have absolutely no impact on the course of history. In 1979, Richard Nixon is in the White House, asking the Justice League to sort out the Vietnam War for him. (They decline.)
Recap Episode: Generations III's 26th Century chapter has Batman and Lara explaining the events of the first half of the series to Superman, who's been away from Earth for the last 500 years.
Refusal of the Call: Unlike the standard DC universe, Hal Jordan declines to become Green Lantern in order to pursue politics, meaning Alan Scott stays GL for several decades more until Kyle Rayner enters the picture. Hal does end up becoming GL when Sinestro goes on a Roaring Rampage of Revenge against all of Earth's GLs, taking out Kyle and Alan.
Retroactive Preparation: Darkseid's plan in Generations III. He sends a massive force of Parademons to attack Earth in the 30th Century; when they fail, the survivors jump back in time 100 years and try again, and so on until they conquer the planet.
The Reveal: The Lex Luthor we've seen for most of the story is actually the Ultra-Humanite's brain transplanted into Lex's body.
Richard Nixon: Shows up in the 1969 chapter trying to get the Justice League to end The Vietnam War or at least silence the anti-war protestors. They reject both requests, declining to get involved in the war because of its Grey and Gray Morality issues and refusing to violate the protestors' constitutional rights. He's also the person to whom Superman gave a Kryptonite Ring ("Because who can you trust if not the President?" Later president Hal Jordan notes the Irony of entrusting such a thing to Tricky Dick).
Roaring Rampage of Revenge: The Dark Age portion consists of Superman hunting down Luthor after he murdered Lois, Kara, and Joel, and Bruce Jr. going all Goddamn Batman on the criminals because of Kara's death.
Sexy Discretion Shot: In one chapter, Batman and Batgirl have a sparring match. She tackles him behind the sofa...and then the same panel is repeated three times, the only change being the hands of a nearby clock moving. When we return to the scene, Barbara is stepping out of the shower and Dick is getting back into his costume.
Sidekick Graduations Stick: With a single unusual exception: Bruce's wife sends him and Bruce Jr. on an adventure, requiring the aged BJ to partake of the Lazarus Pits and become Robin again, despite having been Batman himself. At the end they find out it's because his wife felt bad about never letting BJ be Robin to Bruce's Batman.
In the 1949 chapter, Dick becomes Robin one last time (after having hung up his cape to go into law) to help Bruce with a case.
Significant Anagram: The doctor treating Lois' cancer is Dr. Holurt. Guess who he is. No, really, go ahead and guess. It's the Ultra-Humanite.
Skunk Stripe: Bruce Wayne has one after gaining immortality from the Lazarus Pit.
The Slow Path: After Superman gets sent back in time to the 19th century, Metron puts him in a capsule that holds him in stasis until he can be revived 700 years later, which means Batman finds the capsule just moments after seeing Supes fly off.
Some Kind of Force Field: Green Lantern Kyle Rayner surrounds Ultra-Humanite's hideout in what appears to be green amber to keep greedy villains from raiding it for its secrets; several failed attempts can be seen around the perimeter.
Spell My Name with a "The": In 1939, Batman is known as "The Bat-Man". This even gets lampshaded in a later chapter when Bruce Wayne talks about the time when people referred to Batman "with the definite article".
Spin-Offspring: Superman and Batman generate a dynasty of offspring that take after their forebears. Wonder Woman has her daughter Stephanie, Barry Allen (Flash) has his daughter Carrie, and Wally West (Kid Flash) has his son Jay.
Spirit Advisor: Alfred to Bruce, but the story remains vague on whether it's this trope or just Bruce's imagination. It's probably the former, since Alfred helps bring Dick back from the edge.
Start My Own: In the 1964 chapter, the teenage sidekids and children (Supergirl, Robin II, Wonder Girl II, and Kid Flash) decide to create their own hero group for themselves, eventually deciding on the name "Justice League".
Super Empowering: Humanite-in-Luthor develops a cure for Gold Kryptonite, which Superman uses to restore his own lost powers as well as giving them to his grandson Clark Wayne. In Generations III, Supergirl Blue and Batman use it as well, with the Hand Wave that Batman's immortality let him survive it.
Take a Third Option: In the 1959 chapter, Superman and Batman are "tested" by Mr. Mxyzptlk and Bat-Mite to see who's the strongest, and therefore which one will be taken deep into space to help some aliens in need. They pretend to be killed, which causes the aliens to take Mxy and Bat-Mite instead.
Taking You with Me: Dick Grayson's vengeful spirit tries to kill the Joker, but Alfred's spirit talks him down before he condemns himself to Hell.
Time Skip: Each chapter jumps ahead by a set number of years for each series: 10 for Generations I, 11 for Generations II, and 100 for Generations III.
Together in Death: Bruce Jr. rejects the chance to live even longer, saying that he's kept Kara waiting for over 300 years. The sight of their spirits departing to the afterlife together is enough to make even Batman shed a tear.
Twin Telepathy: Supergirl (Kara Kent) and Wonder Girl (Stevie Trevor) were born at practically the same moment, so they exhibit a degree of empathy, which is how Wonder Girl finds the captive Supergirl, Robin, and Kid Flash when they're captured by the Rogues.
The Unfavorite: Joel thinks he's this due to not having powers, something Luthor gladly encouraged for the sake of his revenge plot. His equally powerless son is given to Bruce Wayne Jr. to raise, in order to prevent little Clark from going the same route as his father.
Unfinished Business: After the Joker kills Dick Grayson, he begins haunting the psychotic clown and comes very close to killing him, until the ghost of Alfred manages to talk Dick into moving on.
The Unreveal: Bruce's wife is never given a positive identity, but it's strongly implied to be Julie Madison; he's dating her in the first chapter, and his wife is from high society.
Unsettling Gender-Reveal: Most of Generations III's 22nd Century chapter focuses on who we (and the heroes) assume to be Kamandi. At the end of the chapter we learn it's actually his identical daughter Kam.
Walking the Earth: Scott Free says that he and Metron have been doing this since they escaped Apokalypse in Generations III.
Wedding Smashers: BJ and Kara's wedding is interrupted when Joel attacks with a suit of Powered Armor, and Luthor takes advantage of the situation to murder Lois.
"Well Done, Son" Guy: After the as-of-yet unborn Joel is De Powered, Superman and Lois make a conscious attempt to avoid this by never letting the child know that he's the Muggle son of Superman. Unfortunately, Luthor decides to tell Joel himself, warping the boy's mind for the rest of his life.
What Measure Is a Mook?: Examined. Darkseid's new Parademons have the ability to think and reason for themselves, whereas the originals were mindless drones. When Lara learns of their sentience, she makes sure that none of the other heroes find out (which includes snapping a Parademon's neck) for fear that this trope would come into play and they wouldn't be able to fight anymore.
What the Hell, Hero?: Said by the Justice League to Batman III (Bruce Wayne Jr.) when his crime-fighting methods become increasingly violent and dangerous. He denies it until he nearly kills Alan Scott and has a My God, What Have I Done? moment.
Whole Episode Flashback: The 24th Century chapter of Generations III goes back to 2008 and resolves a dangling plot thread from Generations II: Bruce's wife saying that Bruce Jr. isn't his son. It turns out she was lying and just wanted to make up for her denying Bruce and BJ the chance to be a team.
Widowed at the Wedding: Bruce Wayne Jr. (Batman) was widowed shortly after the wedding when his newly-wedded wife Kara Kent (Supergirl) was killed by her brother Joel Kent.
Year Outside, Hour Inside: Superman experiences this in Generations III when he's stranded on New Genesis and when he finally leaves, only to come back some time later and find that his children with Beautiful Dreamer are now adults who think their father abandoned them.
You Can't Fight Fate: Double subverted. Clark and his parents find out about Thomas and Martha Wayne's impending deaths thanks to a Kryptonian chronoscope. They manage to warn the Waynes, who decide that Batman is too important to the world and willingly go to their deaths — though they make sure Bruce knows how much they love him before they leave.
You Killed My Father: In Generations III's 19th century chapter, Johnathan Kent is chasing Jonah Hex because he believes Hex killed two of his brothers and a dozen friends during the American Civil War. Hex says that they were soldiers fighting for their countries and it was nothing personal.
Your Mind Makes It Real: The Guardians eventually reveal that the Green Lantern Ring's weaknesses are all psychosomatic: regular GLs are weak to yellow objects because they're told to be, while Alan Scott assumed his ring was weak to wooden objects after a thug clocked him with a baseball bat. Hal Jordan, who figured this out on his own, can use the ring without any such hinderances.