When the series opens, the 31st-century Legion is hopelessly outclassed by the famed Fatal Five. They resolve to recruit the near-mythical Superman from the past, but for undisclosed reasons, Brainiac 5 brings them to Smallville, not Metropolis. There they invite 18-year-old Clark Kent to help them in The Future, promising that with Time Travel, he can return the minute he left.
At Brainy's insistence, everyone studiously avoids telling Clark who he's supposed to become in the future. Regardless, Clark finds the Superman Museum, connects the dots, and takes the costume from the display case, and the name of Superman, for his own. Together they defeat the Five, and the adventures begin.
The show had a very Silver Age tone to it, but the most noticeable and controversial change from the source material was turning team genius Brainiac 5 from a Human Alien into an android. Word of God is that this was supposed to tie him more closely to his ancestor, the original Brainiac, as well as avoiding having to explain how an organic can be the 'descendant' of a robot.
Season Two saw everyone age about two years, even Brainy, and the show went Darker and Edgier after the very light and bouncy first season. The premiere visited a Bad Future where Superman's clone was bred to fight Galactic Conqueror Imperiex, who when cornered escapes to the 31st century and proceeds to wreak havoc as the season's Big Bad.
The series had its own comic series, Legion of Super-Heroes in the 31st Century, which ran for 20 issues, some of them taking place after the end of the show.
Not to be confused with Legion of Super-Heroes (2023).
Legion of Super Heroes provides examples of:
- Aborted Arc: Both Drax and Alexis are forgotten about after their debut episodes, though the latter makes a brief cameo on Takron Galtos in "Sundown".
- Acrofatic: Bouncing Boy is pretty fast for someone of his girth.
- Adaptational Badass: Brainiac 5 of the comics was merely a Teen Genius. Here, he's a robot with Technopathy who can transform into just about anything and extend any limb, and even has a One-Winged Angel form.
- Adaptational Early Appearance: The Sun-Eater storyline that was the death of Ferro Lad was adapted for the finale of the first season — but the Fatal Five, originally formed during the comics version to help out, are already in existence in this version.
- Adaptational Villainy: Brin Londo's father Mar Londo was responsible for giving his son his powers in the original comics, at least in the Pre-Zero Hour continuity, but he only appeared briefly in flashbacks and wasn't in any way suggested to be as abusive and manipulative as his animated counterpart.
- Adaptational Wimp: Karate Kid only got on because the Monster of the Week was nullifying powers. Comic Karate Kid is on the team because he's strong enough to fistfight Kryptonians with nothing but sheer unrealistic training skill.
- Advertised Extra:
- The Fatal Five were only the main villains of two episodes.
- The opening credits of season 2 were full of this. A notable example would be Sun Boy, who has an entire scene shown in the opening of every episode that season even though what was shown in the credits in pretty much all he ever did. There are also characters from season one who keep their spot in the opening despite their roles being significantly decreased that season to only appearing in a few episodes, like Saturn Girl.
- Alternative-Self Name-Change: Superman-X has been known to respond to just Superman, even when the original Superman is around. As a result, the team chooses to call him by the name the original Superman gives him, Kell-El, so that the two can be more easily distinguished.
- Amazingly Embarrassing Parent: Phantom Girl sees her mother, President Winema Wazzo of the United Planets, as this. She knows her mother means well and the two get along better after "Champions" (although that's not to say their relationship was sour beforehand), but she can't help but feel exasperated when her mother becomes overly doting and protective or makes false assumptions about her daughter's dating habits.
- Amnesiac Dissonance: Ron-Karr impersonates Superman with his memories altered to make his imitation more believable in "Who Am I?" He remembers his alignment when Computo's scanning of his memories reveals a memory of the Legion of Super Villains.
- And I Must Scream:
- One interpretation of Ayla Ranzz before she regains her physical form in "Chained Lightning."
- Wizards on Zarok who fail the trial are doomed to spend eternity encased in a block of ice, it would seem. They look terrified, but no one can hear them scream.
- Animal Eyes: Ironically Timber Wolf's are of the slit, cat-like variety.
- Anti-Hero Substitute: Superman X is not quite as nice as the original Superman.
- Arbitrary Skepticism: Brainiac 5 refuses to believe in magic even though pretty much everyone in the Legion has extraordinary powers.
- The Atoner: Dream Girl in her Backstory, who wants to make amends for using her precognitive dreams to con people. Lightning Lad doesn't buy it initially.
- Badass Creed: The LOSH has one as part of their formal pledge of new members: To the Legion of Superheroes, I make this solemn pledge. To use my powers for good. To fight for justice and protect the innocent. To aid my fellow legionnaires in times of peril and to keep their secrets safe. We are the Legion of Superheroes!
- Bald of Evil: Rich Bitch Alexis loses her hair shortly after going off the deep end for Superman, and blames him for it, just like her presumed Silver Age ancestor—naturally her prison uniform reads, in Interlac, "LUTHOR." Unlike her ancestor, her hair grows back, though it's now much shorter.
- Batman Can Breathe in Space: Justified; like the comics versions they probably use invisible "transuits" — in space, everyone can see all of you.
- Battle in the Center of the Mind: Happens in "Dark Victory" when Superman and Kell-El try to help Brainiac 5 defeat Brainiac 1.0.
- Bear Hug: In the season 1 finale, when Superman is saying goodbye to the Legion, Phantom Girl and Saturn Girl hug him only to have Bouncing Boy pull all three of them into one of these. Superman, being Nigh-Invulnerable, is merely nonplussed while you can hear bones creaking and the girls collapse to the ground afterwards.
- Betrayal Insurance: It's Brainiac 5, otherwise portrayed as Superman's
very loyal Robot Buddy, who keeps Kryptonite for emergencies. - Big Bad: Imperiex is the main antagonist in Season 2.
- Big Eater: Bouncing Boy eats every bit of food he can reach.note
- Admittedly, this may hark back to his always-chubby comic original, who gained his powers when he accidentally drank the experimental serum he was supposed to be delivering. (In his defense, the container was exactly the same size and shape as his soda bottle...)
- Book Ends: The first season begins with the Legion recruiting a young Clark Kent and ends with him being returned to his own time. The same applies with Superman X in the second season.
- Brought Down to Normal:
- Superman in "Brain Drain" when under the rays of the planet's red sun. He finds a way to compensate.
- Also briefly in "Message in a Bottle," where he's zapped into the bottled city of Kandor without bringing his power suit to nullify the effects of the red sun (which, due to time travel, he didn't know he had at the time). Luckily, one of his robot duplicates gives the suit to Brainy. Later, after the suit is damaged and Supes loses his powers again, Brainiac 5 uses data given to him from Brainiac 1.0 to turn Kandor's sun yellow, thus reversing this and turning Kandor into an entire city of superpowered Kryptonians.
- Brainy in the finale. He's still smart but he's lost his ability to transform into his giant robot form or stretch his limbs. He essentially becomes a really smart, green human.
- Cain and Abel: Lightning Lad and
Lightning LordMekt are brothers who are initially not on good terms. By "Chained Lightning", however, their hostility towards each other ends. - Calling Your Attacks: In the episode "Champions," Jo Nah (a.k.a. Ultra Boy, who has all of Superman's powers but only one at a time) calls out his powers as he activates them so viewers can know what the hell he's doing, straddling the line between this trope and By the Power of Grayskull!.
- Canon Foreigner: Superman X; several homage characters like Alexis, Zyx, and Drax; and Breath Boy, with the power to hold his breath for long periods of time.
- Canon Immigrant: Alexis Luthor was officially introduced into The DCU in Grant Morrison's The Multiversity series.
- Card-Carrying Villain:
- A bit of a plot point in the episode "Phantoms". Phantom Zone escapee Drax hears the voices of his still-imprisoned parents in his head, constantly reminding him that he's evil and always will be. Supervillains really do make Abusive Parents.
- In the Grand Finale, despite never having self-identified as evil before (quite the opposite, in fact), the still-alive villain says to... no one in particular, "Evil does not die. It evolves," in an ill-fated Sequel Hook.
- Catapult Nightmare: Showcasing that Lightning Lad is surprisingly buff in Season Two.
- Chekhov's Skill: Superman X's Kryptonite immunity. It was mentioned only once, when introducing himself and how his LEGO Genetics make him stronger, however, it never saw any use in the series proper until the finale, where it saves the Original Superman's life.
- Chess Motifs: In "Dark Victory", Brainiac 5's mental battle against Brainiac 1.0 is first represented as the two playing chess with pieces bearing the likenesses of the Legion.
- Civvie Spandex: A bizarre variation. The costumes the superheroes themselves wear are perfectly in keeping with superhero tradition, but the dress of the non-super characters and background characters suggest that this trope may somewhat be the case.
- Clear My Name: "Cry Wolf" has Timber Wolf try to prove that he didn't murder his father. It turns out that he did kill him, but it was a clone and he was mind-controlled into doing the deed by the real Dr. Londo.
- Combining Mecha: Hoo boy. In the Season Two finale: the towering fusion of every Coluan ever, with Brainiac's Skull Ship as the head.
- Composite Character:
- In "Phantoms," Drax is based on a hodgepodge of Phantom Zone criminals, is implied to be the son of General Zod and Faora/Ursa, and has many design elements of the non-Kryptonian Zod from Superman: Birthright.
- Superman X is one of Conner Kent (clone of Superman), Lar Gand/Mon-El (Superman's powers with an immunity to Kryptonite, plus being affiliated with the Legion), and the Superman of the 853rd century (successor of Superman from even further in the future).
- This continuity's Starfinger physically resembles the Char Burrane version, but has the powers of the original Lars Hanscom version.
- Continuity Cameo
- Wait, is that Booster Gold cleaning that museum? With Skeets taking tickets at the door?
- ... Did Alexis just steal Lobo's bike?
- "Jo Nah of Rimbor"?
- And all the voiceless group-shot cameos by Legion members (e.g. Element Lad) and numerous Hopeless Auditionees (Night Girl, Double Header).
- Can you spot how many Green Lantern Corps species are background characters?
- Among the items a bored Zyx conjures up in the background while Superboy... er... man is expositioning are a Green Lantern power battery and Dr. Fate's helmet.
- A dog and a cat resembling Krypto and Streaky respectively can be seen in Kandor in the episode "Message in a Bottle".
- In "Trials," White Witch (a Legionnaire in the mainstream comics) shows up, but as a hologram/illusion contained with an enchanted bracelet tasked with guiding Zyx through his trials to regain his magical powers.
- Conqueror from the Future: Imperiex is from the 41st century and tries to conquer the universe in the 31st century.
- Convenient Coma: Saturn Girl's in a "healing trance" for most of Season 2, while Matter-Eater Lad is similarly indisposed from taking a bite from the Emerald Eye of Ekron.
- Cowboy Episode: "Unnatural Alliances" has the Legion battle Terra-Man and his gang, who are modeled after Wild West outlaws.
- Custom Uniform: Most of the characters' uniforms follow the pattern of a three-part division with a center band of contrast running down the middle, and all of them have the Legion emblem somewhere on their waist.
- Cynicism Catalyst: The death of Lightning Lad and Mekt's sister Ayla. One became The Lancer, the other became the white-haired Aloof Big Brother on the path to villainy. Then Ayla turned up Not Quite Dead, which brought up all sorts of mutual guilt issues.
- Darker and Edgier: The second season considerably tones down the comedy and has the team face Imperiex, who is out to conquer the universe and destroy everyone who opposes him.
- Dark Horse Victory: Possibly the quickest example ever. The new-leader-election is proposed and concluded in about 30 seconds with Bouncing Boy as the new leader.
- A Day in the Limelight: "The Substitutes." Then Arm-Fall-Off Boy gets an entire spin-off comic issue.◊
- Desperately Looking for a Purpose in Life: Alexis. But thanks to Superman rejecting her and stopping her from killing the Legion, she found one.
- Didn't Think This Through: Dream Girl used to work as a fortune teller named "Madame Mysterious" who had a history of conning people, though as she puts it she was only trying to tell people what they wanted to hear. Lightning Lad's still angry about the emotional trauma she put his family through when she lied about them finding his sister on the planet Nema, or more specifically, angry about what it did to his parents. Dream Girl said it was easier sometimes to lie to spare their feelings, without realizing just telling the Ranzz parents she didn't foresee a reunion with Ayla would've been preferable to getting their hopes up for nothing.
- "Die Hard" on an X: In the 10th issue of the Legion of Super Heroes in the 31st Century tie-in comic, Saturn Girl and Lightning Lad fight off the Fatal Five and their Unresolved Sexual Tension.
- Disney Death:
- Happens in "Fear Factory" when Brainiac 5 sacrifices himself to shut down Quavermass-12, but comes back thanks to giving Superman a backup copy of himself prior to entering the space station's mainframe.
- Superman gets his own in the first part of "Dark Victory" when he appears to die from prolonged exposure to a Kryptonite crown. The second part has him recover with the revelation that he merely went into a temporary death-like state to fight off the Kryptonite poisoning.
- Do-Anything Robot: Brainiac 5 can change his arms into any tool or weapon needed.
- Does This Remind You of Anything?: The Sun-Eaters are nothing like stockpiled atom bombs, no sir.
- The Dragon: Validus serves as the muscle to Imperiex.
- Early-Bird Cameo:
- Matter-Eater Lad as Kem the Bismollian contestant in the Space Olympics.
- The Legion HQ's computer system is called "COMPUTO."
- A wizard on the Zarok council is intended to resemble Mordru. But when there is a Mordru episode, it's a different guy...
- Emotion Eater: Quavermass-12 feeds on its captives' fear.
- Enemy Mine: The first Season Finale "Sundown" has the Legion team up with the Fatal Five, while the second season episode "Unnatural Alliances" has Superman X team up with Imperiex to defeat Terra-Man.
- Enemy Within: The finale of the second season has Brainiac 5 taken over by Brainiac 1.0.
- Evil Brit: Drax. Appropriate, if it's true that he is General Zod's son.
- Evil Counterpart:
- Drax is an Evil Counterpart to Superman. They have the same powers and both are Kryptonians since it is implied that his father is General Zod.
- Prior to his Heel–Face Turn in "Chained Lightning", Mekt Ranzz served as a villainous equivalent of his brother Garth due to having the same lightning-based powers and being more selfish and dishonest.
- Evilutionary Biologist: Dr. Londo, Timber Wolf's father. He's the reason why his son looks the way he is and it's strongly implied that he wasn't the only victim of his genetic experiments.
- Ferris Wheel of Doom: Saturn Girl, Bouncing Boy, and Brainiac 5 stop an out-of-control ferris wheel when they recruit Clark Kent in the first episode.
- Fiction 500:
- Alexis is said to have her own planet, or so Saturn Girl claims.
- R.J. Brande probably counts as well, since he is stated to be one of the richest people in the galaxy.
- Fictional Counterpart: The episode "Fear Factory" sees the team watching several horror movies that fall into this, including one for Alien.
- Find the Cure!: "Brain Drain" has the Legion try to cure Brainiac 5 of his malfunctions by exposing him to radiation from a distant planet.
- Flashback Nightmare: The trip to Korbal—for Lightning Lad and Mekt.
- Foreshadowing: Superman X's cryptic message to Brainiac 5 at the Season 2 premiere. This will be followed by Brainiac's last words from the end of "Who Am I?": "But that would mean the potential for evil is also within... all of us." Of course, finally there's "Message in a Bottle."
- Fun with Acronyms: Although it doesn't spell out a word, and it's more like a Mythology Gag: the so-called "Heroes for Hire" Light Speed Vanguard, which will later be known as the Legion of Super Villains.
- Fusion Dance: The final battle against Brainiac 1.0 in Brainiac 5's mind has Superman merge with Superman X.
- Future Imperfect: A lot of details were apparently lost in "the great Crisis." Meaning, among other things, no one remembers the Phantom Zone's name or that it even exists.
- Good Scars, Evil Scars: Lightning Lad has a scar shaped like a lightning bolt over his eye.
- Great Gazoo: Zyx, a Spoiled Brat Mxyzptlk homage who enjoys using his powers to mess with people.
- Grievous Harm with a Body: Because Stone Boy's stone form is immobile, he can pretty much only be used as a blunt weapon by the other Substitute Heroes.
- Heel–Face Turn: Although they weren't seen after their "turns", Lightning Lord and Ron-Karr.
- He Is All Grown Up: Clark in Season Two. "Wow."Timber Wolf (to Phantom Girl): "Please stop saying that."
- Heroic Sacrifice: Ferro Lad gives his life to end the crisis in the 1st season finale, as a nod to the comics.
- How Do I Shot Web?: Superman in the first episode has trouble learning to fly.
- I Did What I Had to Do:
- Brainy, often. Especially when it comes to making sure Superman doesn't learn too much about his future. Turned up to eleven when he becomes possessed by the original Brainiac, who intentionally uses this tendency to worm his way into Brainy's mind.
- Cosmic Boy also lives by this sort of code, which leads to him taking actions that the others may perceive as harsh.
- In the Back: Brainiac quite literally stabs Imperiex in the back in the first part of the Season 2 finale.
- The Jeeves: Alexis' robot Battle Butler, awesomely named Wodehouse.
- Jerk Jock: Mekt Ranzz initially picks on his brother Lightning Lad.
- Jerk with a Heart of Gold: Lightning Lad is very arrogant, but still fights for what is right. In Season 2, Superman X falls in and out of this every episode.
- Jumping Off the Slippery Slope:
- The Light Speed Vanguard, who at first seem Cooler And More Effective Heroes, then Kinda Selfish Mercenary Heroes, then Ruthless Protection Racket.
- Alexis quickly goes from a brilliant but lonely Spoiled Brat with a wild streak to obsessing over her only friend to attempting to kill him for not wanting to be with her... and causing her hair to fall out. Realize who she's a Distaff Counterpart to yet?
- Forget Distaff Counterpart, try "descendant."
- Kid-Appeal Character: As a contrast with the other, much darker elements that accompany the new season, a young Chameleon Boy joins the Legion during the Time Skip.
- Killed Off for Real: Ferro Lad in the finale of Season One when he sacrifices his life to stop the Sun Eater machine from destroying Earth's Sun.
- Laser-Guided Amnesia: The reason every adaptation brings Saturn Girl to Smallville. But by Season Two, in a creepy Shoot the Dog moment to protect the timestream, Brainiac 5 uses a memory-flasher on Superman. Which, in light of the rest of the episode and combined with the self-satisfied look in his eyes is another nail in the foreshadowing coffin that the more ruthless Brainiac 1.0 had infected his mind and would turn up later.
- Laser-Guided Tyke-Bomb: Superman X, a heroic version raised only to defeat Imperiex.
- Laughably Evil: Starfinger. Sweet fancy Moses, Starfinger. He's more dangerous indirectly than you'd expect for a man of such foppish whimsy who is deemed a "third-rate nuisance" by Brainiac, but the slapstick provided by his battles with the Legion of Substitute Heroes is good for at least a couple dozen laughs or so.
- Legacy Character:
- Brainiac 5 is descended from the original Brainiac.
- Gee, I wonder if A-LEX-is, from the episode "Legacy," is a Legacy Character of someone we know?
- LEGO Genetics: With Kryptonite, no less! Superman X has immunity to Kryptonite because it was combined with his Kryptonian DNA.
- Leotard of Power: Dream Girl's default costume.
- Little Miss Snarker: Phantom Girl.
- Lonely Rich Kid: Alexis. Whom Superman befriends. And she loses her hair. Does She Remind You of Anyone? The episode she's in is called "Legacy," for added unsubtlety.
- Losing Your Head: Brainiac 5's head is separated from his body for most of "Brain Drain".
- Magic Skirt: Triplicate Girl's skirt somehow stays in place despite its short length and her frequent movements.
- Master of Illusion: Saturn Girl can use her telepathy to make her opponents see things that aren't really there.
- Mecha-Mooks: Imperiex's army, which he somehow still has after arriving in the past, are unfortunately named "Destructo-bots" at one point. Before that, Brainiac 5 all but served as a renewable Red Shirt, since robot injuries get a free pass from the Media Watchdog, especially one who can self-repair.
- Mechanical Lifeforms: In this version, Brainiac 5's species (Coluans) is a cold Hive Mind of androids.
- Memory Gambit: "Who Am I?" involves Chameleon Boy impersonating Persuader to spy on Imperiex with his memories altered to make him believe he actually is Persuader so that his performance is more believable. It also turns out that Imperiex has infiltrated the Legion with the same method by having Ron-Karr impersonate Superman.
- Men of Sherwood: In "Message in a Bottle", the citizens of Kandor don't join the heroes in fighting Imperiex right away, and initially get battered around easily once they do. Then they are exposed to the light of a yellow sun, get the same powers of Superman, and play a big part in dishing out a Curb-Stomp Battle to the villains.
- Merchandise-Driven: Probably why the Legion ship got unceremoniously blown to smithereens in the second season premiere, only for a replacement to arrive within seconds.
- Messianic Archetype: Superman becomes this in "Dark Victory" when he seemingly dies from wearing a Kryptonite crown only to miraculously return alive and well.
- Mini-Mecha: Alexis built her own mecha-suit.
- Mission Control: Most episodes have someone filling this role. Usually, it is either Brainiac 5 or Bouncing Boy, but occasionally Cosmic Boy fills this role instead.
- Morality Pet: For Mekt Ranzz in "Chained Lightning." Many years ago, dead little sister. Then, Not Quite Dead (which puts Even Evil Has Loved Ones back into play), followed by Unexplained Recovery. As he directly contributes to Ayla's restoration, he surrenders to prison without a fight.
- Musical Nod: A lot of the music is reminiscent of DCAU's themes, especially themes related to Superman — which are very similar to the main Leitmotif in Superman: The Animated Series. Makes sense, as this show was originally intended to be in the DCAU.
- Mythology Gag: Waaay too many to list. So it has its own page.
- Never My Fault: Alexis, the exact same mindset as... well, you know.
- Never Say "Die": Even when they managed to get a Heroic Sacrifice and a murder conspiracy onto kids' TV, they still couldn't call it death.
- No Matter How Much I Beg: Brainiac 5 at the beginning of "Brain Drain", where he's unsure of the aftereffects of the Coluan's alignment process on his brain patterns while detached from their collective (and the balance their Hive Mind setup provides). He locks himself into a containment chamber and makes the others promise to not free him until the ten hours are up.
- Noodle Incident:
- Alexis' experiment. "The top ten floors look as good as new, don't they?"
- Sometime between the first and second seasons, Cosmic Boy was reelected as leader and it's mentioned that Lightning Lad lost against him. Given Cosmic Boy Took a Level in Jerkass by the second season, one has to wonder how exactly anyone was willing to vote for him.
- The Nose Knows: Timber Wolf has heightened senses thanks to being a humanoid wolf and can tell what happened during the faked murder of his father just by scent.
- Obstructive Bureaucrat: The hat for Zarok, the sorcerers' world. According to the head sorcerer it's all necessary to keep its incredibly powerful citizenry from misusing their powers. However, to an outsider, the red tape is strange enough to go from obstructive to totally absurd.
- Oh, Crap!: Imperiex in "Message in a Bottle" when he realizes that he's now squaring off against millions of aliens that have the powers of Superman.
- The Only One Allowed to Defeat You: Superman X for Imperiex.
- Only the Worthy May Pass: "Trials" involves Zyx losing his powers and having to regain them by completing trials that prove he is worthy of them.
- Orifice Invasion: Dr. Londo's nanites infected Timber Wolf's brain by flying through his ear canal while he was asleep.
- Our Werewolves Are Different: Timber Wolf, natch.
-
Out of Order - Pet the Dog: "Unnatural Alliances" for both Superman X and Imperiex. Although, the latter had no choice, seeing as his existence actually depended on it. Followed by a Kick the Dog immediately afterwards.
- Phantom Zone: The Phantom Zone makes an appearance in an episode where a much younger Superman releases a Kryptonian boy born/created by some of his old enemies to, naturally, kill Superman. He should really stop messing with the Phantom Zone projector.
- Pick Your Human Half: Brainy gets a weird version of this in that his more human emotions and twelfth-level intellect are usually at odds, causing conflict within the team and Brainiac 5 himself (particularly in Season 2).
- Pointy Ears: Timber Wolf of the Beast Man variety
- Power Glows: Lightning Lad's eye scar lights up when he powers up.
- Power Nullifier: This series' version of Nemesis Kid can nullify others' powers, in contrast to his comics counterpart, who temporarily gains new powers needed to stop his enemies.
- Preemptive Apology: Brainiac 5 wipes Superman's memory because he had learnt too much about his future.
- Primal Stance: Timber Wolf uses this frequently.
- Prophecy Twist: "In Your Dreams" involves the Legion using Dream Girl's dreams to predict the strategies of Dark Circle and have an advantage over them. Ultimately, Dark Circle capture Dream Girl and attempt to use her to get an advantage over the Legion, but they fail when it turns out that what they thought was a vision of the Legion getting killed was actually a vision of the Legion's holograms.
- Pstandard Psychic Pstance: Saturn Girl in the Season 1 opening credits.
- The Quiet One: Stone Boy. Talk about Personality Powers...
- Ragtag Bunch of Misfits: The Legion of Substitute Heroes consists of several rejected Legionnaire wannabes with powers that were deemed too useless.
- Real Life Writes the Plot: Clark was supposed to be called Superboy, but a copyright lawsuit between DC Comics and the estates of Superman's creators at the time got in the way.
- Recruit the Muggles: In "Message in a Bottle", the citizens of Kandor are initially terrified of the villains, but ultimately step up to give the heroes some backup against them. This backup proves to be unexpectedly formidable when the Kandorians are exposed to a yellow sun and get the same powers as Clark.
- Red Oni, Blue Oni: Most notably seen in their Fusion Dance during the Season 2 finale, Superman (blue) and his clone Superman X (red).
- Robot Names: Superman X's bi-parental unit, K3NT (which tends to make a Late to the Punchline moment once you write it down like that).
- Running on All Fours: Timber Wolf can be seen doing this in the series.
- Sealed Evil in a Can: "Phantoms": Due to Time Travel, Superman accidentally unseals an evil that, it's implied, his future self sealed/will seal a thousand years beforehand.
- Sequel Hook: Season 2 ends with a new Brainiac born from Brainiac 5's "husk."
- Shoo Out the Clowns: Losing one-third of yourself to anti-matter bubbles = This Season Is Serious.
- Shoot the Dog: What Super
boyman thinks he's doing in "Fear Factory" by letting Brainiac 5 sacrifice himself to shut down Quavermass-12. Fortunately Brainiac 5 always carries a spare copy. - Shout-Out:
- "In the Beginning": To both the original Total Recall (1990)'s Latex Perfection and the Scooby-Doo You Meddling Kids line.
- And another in "Trials": "Only magic can defeat magic. Duh!"
- When Brainiac 5 goes loopy while sealed within his containment chamber at the beginning of "Brain Drain," he's seen moonwalking.
- The episode "Fear Factory" opens with the team watching a Fictional Counterpart to Alien, including stand-ins for Ripley, Jonesy, and the Xenomorph.
- Show Within a Show: The episode "Fear Factory" sees Bouncing Boy as a fan of Fictional Counterparts of several horror films, including Alien and even ends up in recreations of them.
- The Smurfette Principle: The show started with female Legionnaires Saturn Girl, Phantom Girl, and Triplicate Girl. And then, in Season 2, the powers that be decided that male viewership would be put off by so many girls, so the girls were incapacitated and/or inexplicably sidelined for many episodes. Particularly irritating, as the Legion has numerous characters with a fairly even gender —and species— balance, and the comics have always averted this trope even all the way back to the Silver Age! The addition of Shrinking Violet in the same season was a very small counterbalance.
- Spiritual Successor: To Teen Titans, at the least demographics-wise. Still a team of super-teenagers, still The DCU, and it started the same year Titans ended.
- Spock Speak: Brainiac 5, who also keeps name-dropping his twelfth-level intelligence. Toned down a lot for Season 2.
- Stable Time Loop: Superman only becomes Superman because he finds out he's going to be Superman, and learns heroism from a team that was inspired by his own future heroism, so...
- Status Quo Is God:
- At the very end of the penultimate episode of Season 1, Bouncing Boy is elected the leader of the Legion. After the time skip between Season 1 and 2 it seems that Cosmic Boy has been made the leader again. So from the audience's perspective Bouncing Boy was only the leader for 2 episodes before they changed it back.
- For most of the second season, Triplicate Girl loses her third self and goes by Duo Damsel. By the end of the series, her third self returns and is reunited with the rest of her.
- Super Zeroes: As always, the Legion of Substitute Heroes, who, also as always, prove to be much more heroic and capable than you'd think.
- Tailor-Made Prison: At the end of "Trials", Mordru is defeated by being sealed in metal, with Star Boy using his weight manipulation powers to sink him to the center of Zerok to ensure he can't return.
- Talkative Loon: Brainiac 5 during "Brain Drain." In spite of this, he actually gives a few crucial warnings to the team (such as "Red ants! Red ants! Superman shouldn't play with red ants" note and "Superman, green rocks kill the last son").
- Team Title: The Legion of Super Heroes share their name with the show's title.
- Technicolor Eyes: Brainiac 5 has purple eyes.
- Telescoping Robot: Brainiac 5's neck and limbs can extend.
- The Only One Allowed to Defeat You: Superman X feels this way about Imperiex. He doesn't take it well when Brainiac 5 beats him to the punch.
- This Looks Like a Job for Aquaman: "Karate Kid" involves the recruiting of a Legionnaire named Karate Kid, who has no real powers, but his strong determination helps him defeat Grimbor after he neutralizes the powers of the other Legionnaires.
- Time Skip: Season 2 takes place two years after the end of Season 1, at least from the Legionnaire's point of view. Superman also returns from the 21st century to aid the Legion, but he's physically grown much older and it is even stated by Brainiac 5 that they need the help of a more experienced Superman.
- Three-Point Landing: In the first season opening credits Timber Wolf performs this near the end.
- To Be Lawful or Good: Any time someone butts heads with the unshakably by-the-book Cosmic Boy. Lightning Lad is especially prone to this.
- Took a Level in Badass: Season 2: the intro theme and the main characters' appearances (possibly justified by them aging along with the audience). Lightning Lad now has a soul patch, for example.
- Transformation Trauma: "Trials" has Mordru inflict painful transformations on the Legionnaires when trying to stop Zyx and Superman X from defeating him.
- Two Guys and a Girl: As per the comics, the Legion's founding trio, Cosmic Boy, Lightning Lad, and Saturn Girl. They're close enough to consider each other family, which tends to lead to a perpetual cycle of striking each other's nerves, arguing, and then making amends.
- Unfulfilled Purpose Misery: Superman X goes through this after Brainiac 5 kills Imperiex. Having spent his entire existence being born and trained to destroy Imperiex to save his now erases timeline, he falls into despair after having lost his purpose in life to another. He ends up finding a new purpose in upholding the Superman legacy and protecting his allies.
- Unwinnable Training Simulation:
- Bouncing Boy fails a training simulation in "Chain of Command", which causes him to doubt whether he's suitable for being leader of the Legion.
- "The Man from the Edge of Tomorrow" begins its first part with Brainiac 5 running a simulation that ends with him sacrificing himself to end the threat.
- Villainous Breakdown: When Brainiac 1.0 starts needing to exert effort to fight Brainiac 5 in their Battle in the Center of the Mind, it becomes obvious that Brainiac 1.0 didn't plan on this nor is he taking it well. When defeated, he gives off an almost uncharacteristically agonized scream.
- Villain Team-Up: The brief alliance between the Fatal Four (Validus was absent because he became Imperiex's minion, which is an example itself) and the Legion of Super Villains in Part 2 of the second season premiere.
- Well-Intentioned Extremist:Brainiac 5: "Do not worry. Soon this agony shall pass, as it will pass from this entire universe. Once my work is complete, there will be no more pain, no more chaos. Only a perfect order imposed by me."
- Wham Episode: "Dark Victory." Brainiac 5 ends up being controlled by Brainiac 1.0, Superman is defeated and apparently killed, and Imperiex is Killed Off for Real.
- What the Hell, Hero?: At least twice, between Brainiac and Superman, with the latter calling Brainy out for hiding both Supes's weakness to a red sun in "Brain Drain" and the original Brainiac's involvement in the shrinking of Kandor in "Message in a Bottle." And also when Brainiac suggested risking the Kandorians lives with Imperiex.
- With the former, Brainiac 5 told Superman he apparently failed to un-shrink Kandor.
- Whole Episode Flashback: Most of "In the Beginning" consists of flashbacks explaining how Cosmic Boy, Lightning Lad, and Saturn Girl first met and how the Legion was founded.
- Writing Around Trademarks: The "young Superman" was clearly supposed to be Superboy, and close look at the lipsync in early episodes seems to support this. DC Comics didn't have access to the name at the time.
- Xtreme Kool Letterz: Lot of X's in the names.
- Yandere: Alexis Luthor. She had no friends until Superman... and she REALLY wanted to keep him.
- You Have Outlived Your Usefulness: With the reversal that the boss has outlived the minion's purposes when Imperiex is killed by Brainiac 1.0.
