They're an Ineffectual Sympathetic Villain team, but does that mean they're bad people who are just too pathetic to be a serious threat, or are they actually misunderstood misfits who never got a chance?
By extension, it's shown that Xavier would gladly welcome them if they wanted to join, but did he try hard enough to reach out to them, or did he leave them to their own devices so as to not have to worry about the difficulties they'd bring?
Lance in particular: Did he really have a heroic side, or was he solely motivated by trying to get Kitty to like him? Can it be both in the end, with Lance starting to do good things just to get Kitty into liking him, but ultimately developed into a better man because of it? In this case, is it Love Redeems, or is Lance just turning Kitty into a prize for him to 'win' by being good?
Scott: Was he just trying to be a responsible though imperfect leader, or just a full-on Jerkass?
Were the New Recruits complete idiots who crossed into Too Dumb to Live, or just inexperienced and excited at the prospect of being mutants that they got ahead of themselves a few times? More specifically, did Bobby/Iceman truly learn his lesson and become a good asset to the X-Men/New Mutants, or were his Too Dumb to Live credential just swept under the rug?
Was Spyke an asshole who was Easily Forgiven only for being a newbie and Storm's relative, or just an budding antihero who was too young and constrained to do it right?
Was Mystique shape-shifting into Risty because she wanted to spend some time with Rogue or to manipulate her daughter into letting her access the X-mansion? Or was it a mix of both? The fact that she did not pursue a similar friendship with her own biological son strongly points to the second interpretation.
All of Magneto's actions with Wanda. Given how powerful Wanda is, her lack of control is indeed something to fear. Having Mastermind Mind Rape her could've been more of a last resort since he did try to resolve things the old fashioned way beforehand. Of course, then there's the question of how much he regretted the act.
Arc Fatigue: Season 2 has very few ongoing story arcs, and due to the fairly standalone nature, drags on without anything particularly interesting happening until the finale episodes, where mutants are outed to the world.
Given the Broken Base nature of the couple, Lance returning to being a hostile anti-villain and Kitty dumping him in season 3 could be seen as this to some. Them seemingly getting back together in the finale, or at least implied, would be this for others.
Avalanche. Due to Characterization Marches On, he went from being a volatile Jerkass with a Hair-Trigger Temper and a shade of Manipulative Bastard in his debut episode who nearly killed Kitty and her parents to spending season 2 as a love-sick, but hot-headed, Nice Guy chasing Kitty, and by the last season settles on being an Jerk with a Heart of GoldAnti-Villain. Some adored him as a result and found his relationship with Kitty to be sweet, while others thought it was forced and thought he came off as a creep (not helped by how some scenes indicated he didn't care for Kitty's consent).
Jean. To some extent there's a great degree of Vindicated by History; for years she was written off as an annoying Damsel Scrappy with a Holier Than Thou attitude, but a lot of this came from the Brotherhood and Scogue fans, and some of the things she was hated for were very much a case of Double Standard. Long after the fact though, many modern X-Men fans who adore Jean Grey cite this show's version as being one of their favorite takes on her.
The New Recruits, especially Iceman, got a lot of hate for their idiocy, while others enjoyed it and found them hilarious. "Joyride" is generally cited as an example of them going too far, though.
"Walk on the Wild Side" is remembered for the X-girls and Boom Boom donning sexy black leather outfits to fight crime.
"Spykecam", the episode where Sabretooth first appears, is better remembered for Rogue and Kitty's dance after Rogue absorbs a bit of her skills. While the show was always well-animated, this got an Animation Bump (and was modeled after a similar dance in Buffy the Vampire Slayer), making for some very smooth and sensual dance moves.
Big-Lipped Alligator Moment: The completely out of nowhere music montage in "Walk on the Wild Side". It even involves something of an Art Shift to look more like a music video - as if the Bayville Sirens were a Girl Group. Jean and Amara dancing in the record store is especially out of character. While it is plot-relevant - showing how Rogue and Kitty got involved - the tone itself is bizarre.
"Walk On The Wild Side" comes off as an Anvilicious "feminism" episode that has just gotten worse with age, but since it's filler, people who dislike it tend to simply ignore its presence.
"African Storm", since the episode is about a shaman from Storm's tribe stealing her soul, when magic is only mentioned a handful of times throughout the entire series. Sadly, this is the only episode where Storm is the main focus.
An episode had Forge's research into how Nightcrawler's teleportation works accidentally release demonic-looking monsters from some kind of Hell dimension.
Duncan Matthews started off as a typical Jerk Jock, but become something far worse in his final appearance. After Jean Grey dumped him when he described her mutant gifts as a problem, Duncan slowly develops a hatred of mutants. After graduating high school, Duncan got a job at a mining company and harassed mutants in his spare time. After trying to harass a couple of the younger X-Men students, former X-Men Spyke drives him off, destroying his car in the process. In revenge, Duncan steals some mining equipment from his job and he and his friends attack the Morlocks, mutants who live under the sewers. Duncan and his gang throw bombs down the sewer, attempting to kill as many Morlocks as they can and then force the survivors to the surface, so Duncan and his gang can kill them with laser torches. While confronting Spyke, a mutant child named Leech intervenes, trying to protect Spyke, so Duncan decides to try and shoot him.
Cain Marko is Charles Xavier's half-brother who uses magic to unlock his dormant mutant gene and became the unstoppable Juggernaut. Resenting his brother since childhood, Juggernaut attempted to kill Xavier, but Xavier defeated him and had him sent to prison. Later, Mystique frees Juggernaut, wanting him to get Xavier's computer Cerebro for her. Juggernaut goes on a rampage, derailing a train, before reaching Xavier's mansion. Juggernaut attempts to kill both Xavier and Mystique after Mystique yells at him for destroying Cerebro. The X-Men and Brotherhood defeat Juggernaut, but Mystique frees him again later. Juggernaut goes on another rampage, heading towards a dam near a small town, attempting to destroy the dam and flood the town in order to wipe out 63,000 lives.
Mesmero is a mind-controlling mutant and a servant of Apocalypse. Originally having limited mental powers, Apocalypse boosted his mental powers and promised him more if Mesero freed Apocalypse. Mesmero takes a job at the circus and encounters the X-Men. Mesmero torments Jean Grey with nightmares to break her will and make her his puppet. Mesmero forces Jean to mind control other teen X-Men, forcing them to steal 3 rings that serve as a key to the first door imprisoning Apocalypse. Mesmero forces the X-Men he mind controls to fight their teammates, while he escapes. Mesmero gets the second key by tricking Magneto into destroying a spider creature that was a guardian meant to keep Apocalpyse imprisoned. Later Mesmero allies with Mystique and take her to Apocalpsye's tomb and announces she is the third key. Mesmero tells Mystique to put her hand on the final door, which turns her to stone and frees Apocalypse. Mesmero knows that Apocalypse will kill millions of people to achieve his vision of a better world when freed, but does not care, wanting the power Apocalypse promised him.
Contested Sequel: While not an actual sequel series, it's got a fair amount of dislike from those who grew up with X-Men, but some others liked this incarnation just fine, if not prefer it. Critics attack the show for its lack of fidelity to the source material, its de-aging of all the mutants to teenage and YA versions of themselves, and toning down of violence. Defenders point out that it's the only animated incarnation of the X-Men that isn't bogged down by Wolverine Publicity (the showrunners made it a point of making only one or two Wolverine-centric episodes per season), it also allows proper space and room for an ensemble cast of mutants, where the relationships don't take attention away from the socio-political metaphor and by introducing X-23, it produced a highly successful Canon Foreigner who was ultimately adapted into Logan, the most critically acclaimed and commercially successful of all the entries in the X-Men Film Series, and as such one can argue that Evolution made a more lasting contribution than the original Fox adaptation did.
Critical Research Failure: The Season 2 episode, "Day of Reckoning", has Amara (Magma) fail to correctly give coordinates in metric and needing to be corrected in what it would be in miles. She even directly claims to "hate the metric system". The problem is that the United States is one of only three countries to not use metric, opting for imperial units instead. Meanwhile, Amara is from Brazil, meaning she should would be more likely to mistake distance in miles rather than kilometers.
The Nightcrawler/Shadowcat fans had a bad tendency to do this to Amanda and Lance. Amanda would usually have her canon-characterization inverted where she was suddenly ashamed of Kurt's appearance, when in the show she was often too encouraging and wanted him to be proud of how he looks. Lance meanwhile would be given a massively exaggerated take on his season 1 characterization, to the point he became a full on rapist in some works. In this case, it seems fans would latch onto brief moments where he's shown grabbing Kitty's arm possessively and dialed up until he was a full on abuser.
Jean was bashed by Cyclops with Rogue fans pretty much constantly, where she'd be turned into a full-on Alpha Bitch to give the more relatable Rogue a reason to fight for Scott. Scott and Jean also got this a lot from Gambit/Rogue fans, seemingly just to make Gambit and Rogue's relationship seem cooler by comparison.
The Brotherhood, as a result of how they became completely ineffective as threats and descended into borderline Friendly Enemies with the X-Men during season 2, often get turned into well-meaning misfits who's only crimes are the result of being manipulated by Mystique and Magneto, while ignoring how they were all serious criminals before those two recruited them and even when on their own, could get into serious trouble and cause massive amounts of damage.
Lance and Pietro get this the most (though, for Lance this was canon in the second season), with Lance becoming nothing but a sweet and caring boyfriend who's perfect for Kitty, while his temper and antagonism towards the X-Men (which was almost always instigated by himself first) that he demonstrates throughout the rest of the series is downplayed completely. Pietro meanwhile is often turned into a Loveable Rogue at worst in fanworks and romanticized greatly for OC characters to fall in love with. Ironically, Pietro was heroic in the comics, but the show version gave him seriousAdaptational Villainy, and while you'd expect this to be a case of people applying the comics canon to the show version, generally it was people who didn't follow the comics who did this.
This series turned Kitty Pryde/Shadowcat into one for the franchise. While pretty well known to diehard fans, the success of the series led to her getting an expanded role in X-Men: The Last Stand. This version's portrayal of her is beloved for her development and All-Loving Hero persona.
Kurt Wagner/Nightcrawler likewise - who was a bit better known and had been featured in a few episodes of the 90s series. But this series boosted his mainstream popularity, again leading to an appearance in X Men 2.
Amara/Magma is the favourite of the New Mutants for being utterly adorable, very likable and extremely helpful in battle when she comes into her own.
Amanda Sefton for managing to transcend being a Satellite Love Interest and showing herself to be among the first characters to accept mutants, and being a supportive friend and girlfriend to Kurt.
While Ray started out as a Morlock in the comics, the writers never clarified just what his connection with them was in the cartoon, other than the fact they were both mutually familiar with one-another. And the implications of that connection has made his back story even more ambiguous, even compared to the other Recruits, given that most of them never discussed their backgrounds. Most of the fans tend to write him, in fan fiction, as the child of a broken home who ran away and wound up with the Morlocks before being found by Professor X. They also tend to explain that the Morlocks actually pretended not to know him, since he left them they saw it as an act of betrayal and have since shunned him.
People on The Other Wiki have made some guesses about Avalanche. Namely, they've guessed he's likely Greek, with 'Alvers' being an Americanized corruption of the name 'Alvez', and that his middle name is 'Domonic' to match his name in the comics.
There were a few fans who started guessing when Ristie popped up that - due to the purple hair, English accent and that her name could have just been a more modern version of 'Betsy' - she was going to be revealed as Psylocke.
Rogue and Gambit ended up being the most popular couple, mostly due to their comic book counterparts, eventually leading to the creators devoting an episode to setting them up (and the final scene implying they were together).
Cyclops and Rogue actually became a MAJOR contender from this series, to the point where most of the creators working on it had to be reminded to give Jean more sympathetic character development to make her eventual coupling with Scott more acceptable. Even so, series creator Frank Puar made no secret of the fact that had the show continued into future seasons, Scott and Rogue would eventually become a couple following Jean having a lethal encounter with the Phoenix.
Puar: We played the relationship card with Scott and Rogue, she makes a play for him, and why not? If anyone has an idea of what she's going through, it would be Scott. He lives in fear of losing control of his powers and killing someone; so does she. He had a lousy childhood; so does she. He always feels isolated because of his powers and of his responsibility; so does she. And he's the one who reached out to her and brought her into an environment of warmth, family and friends. Why wouldn't she make a play for him? She reads Jean's actions toward Scott as mean. Jean is a player, the cheerleader who has everything, and can't make up her mind at what she wants. Scott is an item to her, just like Duncan, and who knows whom else. Rogue thinks Jean is a dumb ass and cannot recognize a good thing when she sees it, so yeah, she's going to make a play on the guy. (Oh, as a minor side note; on the final episode, during the peek into the future, check out who is not included in the group shot and check out whom Rogue lands next to.)
Nightcrawler/Shadowcat. It was mostly a side-effect of porting their relationship from the comics to the show. Kurt's canon crush on Kitty prior to dating Amanda and their consistently close friendship after probably helped, along with them being the biggest Ship Launchers in the fandom.
Storm and Wolverine are an odd case as they did have a few genuine Ship Tease moments, fans just wanted way more of it.
The show seemed to set up a few of the X-Men and Brotherhood as having counterparts on the other side. Avalanche with Cyclops wrote itself with their rivalry. The same can be said with Toad with Nightcrawler and Spyke Quicksilver.
Magneto with Xavier! Those to have so much Unresolved Sexual Tension between them it isn't funny. There was the suggestive looks, the fact that Magneto protects him at several points in the series and Xavier's unfailing objections to putting an end to Eric. This can cross to Ho Yay when Magneto does a HeelFace Turn (or in the origin when they were still on the same side).
Wolverine x Mystique. Pretty much all the banter they have, especially in "The Cauldron, Part 2", makes them seem Like an Old Married Couple. The fact that they sit next to each other on the XM Velocity adds to this.
Growing the Beard: The show has decent to average quality in season 1. Near the end of season 2 and the beginning of season 3, however, the show becomes more serious, while still retaining its playful humor, and focuses more on characterization and action. Seasons 1 and 2 focused more on introductions and romance respectively.
The Four Horsemen of Apocalypse in this show were Magneto, Storm, Prof. X, and Mystique. Storm and Magneto would be adapted as Horsemen again in the movie X-Men: Apocalypse, with the latter two being the catalysts to their HeelFace Turn during the film's climax.
In "The Cauldron, Part 1", a few details in the fight between Storm and Mystique became much more amusing with time:
Storm says she doesn't care why Mystique chose to attack her, then hits her with a vicious punch that knocks her out. In X-Men: Apocalypse, Storm says that she idolizes Mystique.
Storm says "This is my home, and you are not welcome here!" to a character whose real name is Raven. Then in Teen Titans, the same line is spoken by a character whose real name is Raven. In both occasions, the line is delivered during a climactic battle of the season's finale.
The Brotherhood watching the Powerpuff Girls in "Dark Horizon" ends up a bit funny as a majority of the cast from the show ended up working on Powerpuff Girls Z later on.
David Haller/Legion appears in one episode, with more realistic short blonde hair instead of his infamous look from the comics. Years later, his only other on-screen appearancealso went with short blonde hair.
The episode "Spyke Cam" has Spyke get a B on a test over the The Star Wars Program because he confuses it with the film it was named after. Much later, Disney would end up buying both Marvel and Lucasfilm to bring both properties under the same roof, making the joke even more humorous.
The Season 2 episode "Power Surge" makes a throwaway reference to pineapple over pizza in 2001, which was long before debates over the topping would take the Internet by storm.
Meghan Black, who voices Rogue, later starred in the 2002 remake of Carrie - also about a teenage girl with superpowers.
The show shares half its cast with another Canadian cartoon about empowered teenagers - Class of the Titans. Kirby Morrow plays The Leader in both. Colleen Wheeler plays the antagonist Mystique here, but is The Mentor in the latter.
Yaoi fans were particularly interested in what Avalanche and Quicksilver did with their free time together living in the Brotherhood Boarding House.
Nightcrawler and Cyclops:
In "SpykeCam", Evan says, "Scott's pretty stiff, but Kurt usually takes care of that." Can't make this up.
The scene where, after the mansion is destroyed and characters have to share rooms, Scott and Kurt emerge from their bedroom with Scott being covered in Kurt's fur.
In "Walk on the Wild Side" Scott at one point grabs Kurt and tells him to cancel his plans for the night with a mischievous look, without context it has some heavy homoerotic connotations, something fans were quick to pick up on looking back at it.
Risty asked Rogue to a Sadie Hawkins dance. That is literally what happened; Scott was taken, so Risty suggested that she and Rogue go. This, of course, makes the reveal that Risty was Mystique this whole time VERY awkward.
Storm's fight with Mystique in "The Cauldron, Part 1" is Orgasmic Combat at its finest. Not only is there a lot of tackling, embracing, and other forms of intimate contact between the two, but the fight is accompanied by large amounts of rough grunting and panting, and when Storm finally knocks Mystique unconscious, they both audibly climax at the same time.
Idiot Plot: Say what you want about most of the episode, but "Joyride" falls apart pretty quickly when you remember Wolverine's advanced senses and Xavier and Jean's telepathy, either of which should have identified who was the culprit instantly.
Evan evolved into this. While he was probably the X-Men's most Jerkass member, he developed into a Woobie during Season Three after anti-mutant sentiment caused former friends to start bullying him. While they were all suffering, Evan was the only one to be shown repeatedly being picked on for his powers, all the while also slowly but steadily losing control of his very visible powers. Eventually, he takes a Mutant harming poison (which were supposed to be a toxin eliminators) and completely loses the hang of his abilities, so the poor kid moves in with the Morlocks as, despite the X-Men's good intentions, the Morlocks are the only ones who can understand his pain. And worse, its unconfirmed if they stop being poisoned by Power8 or if the effects will ever wear off, and they never mentioned if there was a cure.
A big reason why the Brotherhood were so popular, and what fuels a lot of their Draco in Leather Pants, Die for Our Ship, Rooting for the Empire fans. They're all criminals even before being recruited, but they're also all basically without any real parental supervision and essentially live in poverty due to none of them having a source of income. To a lot of people, this makes their criminal behaviour and antagonism sympathetic.
Both Kitty and Kurt are beloved by shippers. It likely stems from their popularity, or their easiness to relate to, but Kitty's pretty much shipped with every guy in the series, and Kurt's shipped with everyone, everyone. You would thinksave for Rogue, but nope, he's shipped with Rogue, too. Never underestimate fanfic.
The Brotherhood also seem to end up with everyone. Well at least Lance, Pietro, and Toad. The Blob aka Fred Dukes, doesn't exist in fanfics.
Moe: Amara is so shy and cute that she's incredibly endearing. It doesn't stop her from being a Badass Adorable.
If Mystique didn't cross it when she replaced Xavier and tried to kill the New Recruits, for no reason other than them being unable to fight Magneto, then she did it when she kidnapped Scott, stealing his Power Limiter ruby quartz glasses, and leaving him stranded in the middle of nowhere, repeatedly attacking him and eventually trying to kill him while he's unable to see. All to get back at him for leaving her behind when she refused to tell them where she imprisoned Xavier.
There was also the soft-drink manufacturer who unknowingly laced his drink with mutant poison. You can tell he's genuinely surprised... then Mood Whiplash kicks in and he figures he can make a lot of money off the discovery. It ended up not going anywhere, however.
Apocalypse was planning on using his machine to turn the populace into mutants... But even he notes that this may kill much of the human population, due to their bodies not being able to take it. He still was willing to go through it.
More Popular Replacement: Iceman ended up filling Spyke's role as the annoyingly rebellious member of the team. But thanks to the lack of Totally Radical, the character being intentionally an idiot (yet still coming through for the team and being pretty competent) and the fact that he was one of the original X-Men in the first issue means he's better received.
Wanda's flashback to when her father carted her off to a mental institution might have been more emotionally effective if they didn't use the exact same voice clip of her crying out to her father three times in the flashback, with those being her only lines aside from "Don't leave me...".
When Professor X is revealed to be Mystique in disguise, the drama of her line "things are about to get much worse" is ruined when there's a pan of everyone else making scared faces that just look goofy.
Scott was a bit of a stick-in-the-mud but was overall a decent guy. However, "Joyride", where his rivalry with Lance was played up to give Lance an antagonist as he tries to join the X-Men, and as a result Scott became the biggest punching bag for Brotherhood fans. Ironically, he actually made a lot of good points against Lance's membership and did try to be friendly, until Lance's disrespect pushed him into retaliate, but people ignore this and focus solely on how he turned the Danger Room machine on to humiliate Lance in front of others.
The New Recruits are only remembered by some fans as Too Dumb to Live assholes, thanks to the same episode. Even though their learn their lesson after, some blame them entirely for Lance quitting since they willingly allowed him to take the blame for their stunts, and as a result some seem to think they were only ever shown as incompetent dumbasses.
Mesmero's introductory episode was this from the beginning to the end in episode 25 (Mindbender). There was no blood, no ultra violence, no huge fights... just him kidnapping and brainwashing a bunch of innocent kids ( Jean, Kitty, Evan and Kurt), using them to set off his Evil Plan to wake up his master Apocalypseand slipping unnoticed under their caretakers' watch. And he starts this by entering the kids's dreams and turning them into nightmares. Poor, poor Jean Grey.
Blind Alley wasn't much better. Scott gets stranded in a deserted town as Mystique's revenge for him derailing her Evil Plan without his visor, completely unable to even open his eyes or he'll blast everything on sight into nothingness...
Apocalypse straddled the line, helped by the fact he wasn't particularly wordy in this continuity.
Spyke, who after living with the Morlocks, became a powerful, mutant-protecting vigilante that can light his spikes on fire.
Jubilee is often regarded as the most useless X-Woman to the general public (comic audiences feel differently though); here however, she's an Ensemble Dark Horse.
Romantic Plot Tumor: Brotherhood fans and Scogue fans consider Scott and Jean's relationship this, as to be expected given how often they received Ron the Death Eater treatment from them. It took three seasons of them developing from close friends into a committed couple, so for those wanting to see Brotherhood hijinks or those that wanted Scott with Rogue, their time together is a chore.
Rooting for the Empire: The original Brotherhood members just don't come off as evil to many fans, despite all the horrendous things they did including rigging a train accident to look like heroes one last time and then fleeing when they discover it's going right at another speeding train with eight tankers of fuel. Even with this, however, they spent so much time when in the spotlight being more Chaotic Neutral than outright villainous that many took a shine to them and thought that they'd be far more fun to hang out with.
The Scrappy: Spyke was an example of the crew's attempts to bring in a brand new X-Men character for the series who would be the "epitome of cool." This failed so badly (with almost all of the fans being irritated by his "cool lingo"note "Yo Rogue, why don't you shed them gloves and give K-Girl a tiny tap?", overall skater persona, and being kind of a jerk who often forgot the lessons taught to him). Though he got seriously Rescued from the Scrappy Heap over time, generally in the popular census, if anyone brings up his character, its usually to say what a lame character he was.
Seasonal Rot: Season 2, due to its over-focus on romantic side plots, less focus on their battles and less action, though the ending managed to fix that by revealing The Masquerade, leading to it Growing the Beard in Season 3.
Slow-Paced Beginning: The first two seasons of the series are mostly episodic, introduces what could be considered too many characters, and drag on for quite a while. But upon the Season 2 finale, and the beginning of Season 3, the series begins putting emphasis on much longer story arcs, and the core themes of discrimination that the franchise is known for.
Strangled by the Red String: Liked or not, Kitty/Lance pretty much came out of nowhere. Season 1 had no indication there was any attraction between them, but in season 2 Lance suddenly has a crush on her which she starts to reciprocate shortly after. There was a Deleted Scene where he saved her from some falling rubble which is likely when the writers intended for her to change her opinion of him, but even that was following him trying to destroy the school and the falling rubble was directly his own doing.
Strawman Has a Point: Magneto as always. He was presented as an extremist for believing that humanity and mutants couldn't co-exist and his plans to build an army of enhanced mutants to defend mutant kind were presented as villainous...but then when mutants are revealed to the world, they're met with hate, and until the X-Men proved that they could use their powers to protect normal people, the world was readying up to round them up and imprison them. Exactly what Magneto believed would happen. Though Magneto did reveal mutants publicly in the most shocking manner he could, seemingly to encourage this reaction from humans, but this was while they were battling the Sentinel, a machine created by one of the few humans who knew they existed, showing that this view was always bound to exist even without Magneto's interference.
They Wasted a Perfectly Good Character: The New Mutants rarely got any focus episodes; Amara, Bobby, Tabitha and kind of Ray (he never gets an episode to himself but plays prominent roles in a couple) are the only ones who do. Jubilee and Wolfsbane got it worst; they were Put on a Bus in Season 3 to keep the cast smaller, not even returning for the fight against Apocalypse. Wolfsbane at least appears in a flash forward in the finale, suggesting they did rejoin the team eventually.
At the end of "X-Treme Measures", the creator of the drink promises Professor X to stop selling the drinks. But when Prof. X leaves, the creator gets out his phone and calls someone to tell them about it, with obvious malicious intent toward mutants. But it never goes anywhere and we never hear about it again. This, along with a few lose plot threads found in the fourth season, could probably be attributed to Marvel deciding to axe the series.
In the first season, it emerges that Magneto experimented on Kurt when he was a baby, resulting in Kurt's demonic appearance, and he is adamant that Mystique not tell Kurt anything about his past. Head writer and producer Greg Johnson explained that "The way we see it, Magneto experimented on him in an attempt to trigger the X-Gene, and succeeded," but why Magneto is so adamant that Kurt doesn't know the truth about his past is never elaborated on.
Several plots and ideas were left hanging, including-but-not-limited-to Jean becoming the Phoenix and the debut of Mister Sinister, or the David/Legion plot, Gambit and Colossus potentially joining the X-Men, etc. The last season was only 9 episodes long, meaning that many of the plans they had couldn't come to fruition.
Several minor characters had hints of complex backstory elements, such as Ray's history with the Morlocks, or the tease that Colossus was Forced into Evil by Magneto, but ultimately none of this is explored. Piotr also had a Ship Tease with Kitty that never went anywhere.
Toy Ship: Multiple gets shipped a lot, despite being younger than everyone.
Lance's romantic subplot with Kitty starts with him saving her life from an accident that he caused. He had also previously attempted to attack Kitty, and due to the nature of his powers, he tends to cause a lot of collateral damage (sometimes near schools populated by children who are never confirmed to have gotten out alive). To some people, all this makes it kind of hard to believe that Kitty would want him for a boyfriend. This also puts him in the somewhat unusual situation of being a common victim of both Ron the Death Eater AND Draco in Leather Pants.
Jean in the infamous "Walk on the Wild Side". Her complaints about often being mistreated because of her gender or being considered a Damsel in Distress are a complete Compressed Vice - considering she was put in charge many times before and shown respect by most of the others. It makes it come across as Wangst, especially since her tantrum is kicked off when Scott saves her from a falling boulder.
Kurt in Season 4 for trying to persuade Rogue to be okay with him keeping the petrified Mystique in the manor. Here's the deal; Mystique treated Rogue far worse than Kurt. Kurt was only accidentally abandoned as a baby when she was fleeing from the wolves - after she had expressed fury at what Magneto had done to him. And besides masquerading as his principal and later Professor X, he didn't really suffer because of her. Rogue meanwhile? Mystique knowingly abandoned her with Destiny and, when her powers awakened, resorted to Gaslighting her to convert her to the Brotherhood. Then she posed as a friend to become Rogue's confidant for months, ostensibly to spy on the others and break into the mansion. Finally, when Rogue was still reeling from the trauma of that revelation, she willingly worked with Mesmero to Mind Rape Rogue into draining her friends and then reviving Apocalypse. This also gives Rogue massive second hand guilt over the world being endangered, and Kurt knows all of this - yet he brings the petrified statue back to the manor even when the reason it was sent away was because Rogue was understandably bothered by having a tribute to the woman who used and abused her multiple times. While the attempt was at Both Sides Have a Point (Kurt seeing more of Mystique's potential for good than Rogue), Kurt comes across as insanely insensitive to Rogue's trauma. Thankfully as of the finale, he tells Mystique to get lost along with his sister.
Spyke honestly did a research report on Star Wars when the subject was "The Star Wars". To an outsider, that's understandable... except in high school you only get an assignment after at least five weeks on a subject!
He uses his camera to record Wolverine's training session... while SKATING TOWARDS HIM! Also, his recording any mutant in general, especially since in the previous episode, they mention keeping mutant activites a secret.
Though she's typically competent, one episode has her let The Juggernaut out of prison, after which she expects to be able to just order him around and just plain insults when he doesn't act obedient, even though he has no reason to listen her. This would have ended in her death if the X-Men and the Brotherhood didn't come rescue her and Xavier.
Lance often uses his powers inside. His power is generating vibrations to induce seismic activity (IE, make building-destroying earthquakes). His power has, on multiple occasions, resulted in buildings collapsing. He still uses his full power when inside, and more-often-than-not has to avoid the damage he causes himself.
X-23 is a clone of Wolverine that was raised from childhood to be a living weapon. She has never had any friends and lived a torturous life without any opportunities to feel happiness. In her first appearance, she breaks down in Logan's arms.
David/Legion, who was first told by his mother that his father Xavier abandoned him, then he moved to a new place where he had no friends, and then was slowly taken over by an alternate personality. An alternate personality that kidnapped and held him hostage in a castle. Then he gets permanently taken over when his dad tries to save him. Poor kid. Because the series was cancelled after Season 4, this becomes a case of The Bad Guy Wins, at least as it stands - there are hints he could've been still saved had the show continued...
It's one of the staples of the franchise that almost every named character is a woobie to some extent. Scott's parents both died in an accident that also caused him to lose control over his powers, Jean's powers are extremely dangerous and hard to control despite how much she works on them, Rogue cannot touch anyone without causing them extreme pain, Kurt has to deal with the fact that his mother is a supervillain and is ostracized because of his appearance, Kitty is bullied for being too smart, Logan has no memory and was victim to experimentation that still causes him to have episodes of PTSD... And that's just the important characters.