Dance of Romance: Chapter 260 has two of them actually: one by Negi and Asuna and the other one by Kotaro and Natsumi.
Dangerous Forbidden Technique: Magia Erebea was originally advertised as a technique quite dangerous to its user, though Negi seemed to have little trouble with it. At least, not until after his fight with Rakan, at which point it began affecting his soul itself. While Negi's body was able to deal with this on its own eventually, this was only by first petrifying him and then turning into something non human, though with Magia Erebea finally under control.
Darker and Edgier: Akamatsu-sensei appears to be rapidly accelerating his use of this trope. Chapters 277 and 278 feature Rakan and a boatload of Mauve Shirts being dissolved into flower petals, and the dozen-odd chapters before it feature an ominous secret that borders on Go Mad from the Revelation, the story of someone who saved the world being sentenced to a brutal death for it, and Negi nearly murdering the wrong person for revenge.
Darkest Hour: Well, see above. Most of what happened after the Governor's ball trumps their previous predicament in awfulness.
To see how bad it's gotten since then, see Total Party Kill. It doesn't get much darker an hour than that.
Dark Is Not Evil: Varies, but the few right bastards have all been humans with no explicit connection to darkness.
Also, Kagetarou, who looks like a villain at first but turns out to be Jack Rakan's buddy. Now we have a shadow-user named Dynamis in Fate's group, and this new guy is quite evil, erasing people from existence and making it quite clear that he intends to kill Nodoka, even using her as a shield and coming close to snapping her neck before Setsuna saves her by hacking off his right handnote He seems to believe that he's doing them a favor by killing them. Then there's the whole summoning shadow demons thing he does, including a huge one.
The demons showcased so far have all been perfectly amicable, at worst neutral characters who just happened to be hired by the enemy team and don't seem very pleased at having to cause serious damage. Justified in that the "Demons" are a race of the Magical World. The more demonic looking ones are a different kind of demons. The demons summoned in the Kyoto arc are oni. Setsuna and Kotarou are half-Youkai (Han'you). Demons like Mana and Poyo are a different kind as well.
A basic principle of Magia Erebea is accepting oneself, including one's worst emotions. In Negi's case, his explicitly murderous thirst for revenge. While not necessarily "evil", it still leaves him unstable and the desire seems to be amplified by Magia Erebea.
Day in the Limelight: Almost every girl gets a chapter, or even an entire arc, devoted to her. Especially if she hasn't had much "screen time" yet.
Lampshaded when Negi (in his bishonen form) tells Ako that `everyone's the main character in their own life'.
Deadly Upgrade: In order to become strong quickly enough to beat Fate, Negi chose the "path of darkness" Magia Erebea, an ability set that isn't suited for human use. While first it appears okay, it begins badly affecting his health and mind. Eventually, it stops killing him, but only because he stops being human at all.
Deal with the Devil: In Asuna's backstory in the anime, she made a deal with demons where they'd stop following her and breaking stuff, but she'd die on her fourteenth birthday.
Death of the Hypotenuse: Doesn't actually occur, but Haruna points out that this is how love triangles usually end, causing the two girls involved to freak out considerably.
Declaration of Protection: Setsuna says several times that she will protect Konoka with her life. Asuna does this to Negi as well... Unfortunately for her, she does it in front of a very large crowd and it's very easily misinterpreted for something else.
Rakan's favourite method of dealing with cute female enemies.
After some Character Development to open up more, Setsuna becomes more susceptible to embarrassment and gets an Attempted Rape scene during a fight with Tsukuyomi as a result of getting distracted when her clothes are forcibly removed by a Demon Charm. Of all things, Setsuna was most humiliated by the fact that she was nearly defeated, since she takes it as a sign that she's getting rusty.
In chapter 354, Paio II makes her reappearance, completely stripping Yue and applying some serious Skinship Grope almost to the point of Black Comedy Rape. She even goes as far as to lampshade that she should overcome this weakness to become a better fighter.
After Negi beats Eva, he makes her agree to go to class properly and whatnot.
Kotaro is just a mercenary, so after he has fun with his fight with Negi they become friends after Kotaro returns to give him a warning.
Later, Negi declares he will make friends with Fate Averruncus after realizing that Fate and Cosmo Entelechia really are trying to do the right thing.
After Chisame beats Chachamaru in a hacking duel, Chachamaru starts dragging her around everywhere, which apparently means they're friends. Well, Chisame does like being dragged around so she can pretend she isn't having fun.
Defecting for Love: Given some developments involving Negi inadvertently romancing one of Fate's most trusted subordinates out of her disguise against her will and creating a pactio with her at the same time. Add the fact that her perfect disguise seems to drop only during times of intense emotion felt on her part, such as love, and it's as good as done.
Deliberate Values Dissonance: Slavery is a state-sanctioned practice and completely normal in Mundus Magicus. Seeing how they use Latin as (one of) their main language and that the political powers date back to Middle Ages if not Ancient Rome, this is to be expected. The current slave system was created by Queen Arika to deal with the thousands of Ostia's homeless after the destruction of their country. Slaves can buy their freedom and are protected against "excessive mistreatment", which the Slave Collar reports automatically, but the electrifying feature of the Slave Collar doesn't seem to fall under "excessive mistreatment" until the heroes beat the the crap beat out of a guy who did it and told him that he was going too far. There might have also been other, off-screen punishments, it was explicitly stated that it's only supposed to be used if a slave revolts or a similar extreme scenario scenario.
Departure Means Death: Magic World natives cannot survive on Earth, so when the magic world goes they'll go with it. Albireo may be an exception, but he might just be a book instead.
De-Power Zone: The execution site in the Magical World completely nullifies magic. Of course, Nagi Springfield doesn't care about that and rescues Arika from it anyway.
Designated Girl Fight: Odd gender inversion: despite the series having far more women than men, the majority of Negi's opponents have been male. At this point, the only named male characters he hasn't fought are Eishun, Johnny, Filius Zect and some of the magic teachers.
When Asuna dies in Negima!, Negi splinters like a broken broomstick. His artificial cheerfulness masks it temporarily, but it quickly becomes ghastly.
In the original manga, Negi probably crosses this after Fate attacks his students at the Gateport and scatters them across Mundus Magicus. It isn't quite as bad as in the anime, but the fact that he was completely unable to protect them after he promised to do so really gives him issues later on.
Played for laughs after Rakan's hilarious first failed attempt to teach Negi Magia Erebea. "I'M GONNA DIE."
Rakan MADE this happen, purposely depressing the crap out of Negi after his "Make a bad face and punch!" initial plan doesn't work. Also those were meant to be strong punches, Rakan told him to do 1000, which even for normal people would be quite tiring.
In the manga, this artifact has a completely different purpose and gets explained in detail. But in the anime it's an Ass Pull that's immediately used to solve what had been an apparentlyunsolvableproblem.
Diagonal Cut: The finishing blow to the Tsukuyomi fight. Somehow.
During the Magic World's final battles, a much more literal example: when Quartum pulls out his final move, EnteiShoukan, Negi jumps out with Raisoku Shundou and literally socks it across the face!
Dirty Business: Negi wonders if defeating Chao's plan to reveal The Masquerade was the right thing to do throughout the Festival Arc. He's reassured by Chao herself, no less that there are no hard feelings, though.
Dirty Mind-Reading: Nodoka gets a heavy dose of it from Paio: "Although one of them was just really screwed-up..."
Do Androids Dream?: Chachamaru begins stressing out and wondering if she has a soul around the time the Magic World arc begins. She eventually gains a pactio and therefore proof that she has a soul.
Dodgeball Is Hell: Very early on, class 2-A engages in a pretty intense game of dodgeball with a class of high school girls.
Does This Remind You of Anything?: Chachamaru needs to be fueled with magic every day to stay in peak condition. It feels good on its own and even better the more magic is poured in. The subtext couldn't have been more obvious if there had been a subtitle saying, "OMGSEXLOL!" During the ball, she has the robotic equivalent of The Immodest Orgasm when Negi gets too into it. After getting back home refuels herself at one point, so of course Eva walks in.
Double Standard: Abuse, Female on Male: While this doesn't occur much (likely due to the fact that Negi is only ten), in one story arc where Negi gets aged up to 15, he suffers a few smacks in the face. Anya, his best friend from home, is also able to beat him up as much as she wants since they're the same age.
During the school festival when ever someone would confess Mana would only shoot the guy
*Drool* Hello: Twice, with the same occidental dragon in the underground beneath Mahora.
Drop the Washtub: Characters can make a washtub fall on others' heads by casting it as a spell.
Drum Bathing: Kaede and Negi share a barrel in an early chapter.
Dude, He's Like, in a Coma!: Chisame tries to get her pactio kiss while Negi is asleep, but he wakes up in the middle of it and she has to do it the normal way (although she covers his eyes).
Dueling Messiahs: Negi and Fate. Negi and the gang eventually discover that Fate and the Cosmo Entelechia are trying to save the human inhabitants of the Magical World, which is about to collapse and in turn cause the humans to be stranded on Mars, the landscape of which was used to create the Magical World. Negi opposes their plan to send the humans to a never-ending dream world by sacrificing Asuna and the Magical World's non-human inhabitants, and tries to get them to help him find another way.
Anya's greeting to Negi is a flaming kick out of nowhere and Asuna kicks Eva right through all her barriers as a greeting sometimes.
As a rather amoral, energetic girl Haruna is quite fond of saying hi by kicking people in the head.
Early-Bird Cameo: Despite being listed in the class registry, Sayo didn't make her first appearance until chapter 74 in the manga. Every adaptation since have gone out of their way to introduce her earlier and most leave her visible to the audience long before any of the characters take note of her presence.
Easy Amnesia: After the Gateport incident, Yue had the bad luck to land right in front of a magic student who accidentally erased all the memories about her life with a memory erasure spell, and was too embarrassed to say so, so she just told Yue that she bumped her head.
Ecchi: It is an Akamatsu manga, after all. At times the series stops just short of explicit.
Eldritch Abomination: Two so far: the demon that Evangeline curb-stomped in the Kyoto Arc, and the huge black shadow-demon summoned by Fate Averruncus' shadow-using minion in the Ch. 270's.
Appropriately, this one also gets curb-stomped, this one by Chachamaru's Kill Sat Artifact.
Elemental Baggage: Subverted in the literal sense, but invoked by Evangeline and Chao's high-level elemental spells. The supplementary materials at the back of the tankobon explain that Kosmic Katastrophe breaks the Laws of Thermodynamics, and that freeze spells are considered higher-level than fire spells because they break more laws.
Elopement: Nagi suggested doing this with Princess Arika when he realized she had developed feelings for him, getting a blast of magic in response. Ironically, they end up eloping after he rescues her from her execution.
Evil Chancellor: A group of them has been manipulating the Megalomesembria Senate and is responsible for every major event that has happened in the story so far, starting with the war. Even the events of the Festival Arc may have been a result of their actions.
Evil Is Easy: Rakan laid out two paths for Negi. He could stay on the path of light and be as tough as Rakan or Nagi in, say, five years or so. He could also take the path of the heretic, choosing black magic to gain that kind of power in mere weeks. It's not quite evil, but it's incredibly dangerous to not only himself but those around him as well as damaging to both his mind and soul.
Exact Words: For Negi's apprenticeship test, Eva gave the conditions "If you can hit Chachamaru even once with your Kung Fu, then you'll pass. The match continues until you're dead and you can't attack anymore." This backfires on her when she declares the match over after Negi was completely thrashed, only for him to stand back up, stating that there's essentially no time limit since the condition was "until I die". He manages to get a hit in while Chachamaru is distracted.
A few of the girls are based off of the characters from Love Hina: Naru (Asuna and Chisame), Shinobu (Nodoka), Kaolla Su (Ku Fei), Motoko (Setsuna, Akira and possibly Madoka), Kitsune (Asakura) and Mutsumi (Chizuru).
Extreme Graphical Representation: Chisame's artifact lets her mentally enter the computer system, Tron style, for super-hacking. Some of the extreme graphics include viruses that look like jellyfish, Magical Girl anti-virus programs which she leaves her Ayaka and Makie during Mahorafest, and Clothing Damage to represent data being destroyed.
Extremely Short Timespan: The Festival arc spanned only 3 days June 20-22, 2003 but took up half the manga up to that point — 9 volumes.
False Start: Nodoka attempts a confession a few times before getting halted, but eventually gets it out. Unfortunately, she did it too early in the series.
Fan Disservice: There's a surprising amount of Squick in the series, since many fight scenes against severelymessed-uppeople occur with the girls in various states of undress. There's also guys in states of undress.
And more than one Fanservice Extra: One girl that shows up for a single panel in the magic world encapsulates about 12 different Fanservice Tropes and adds nothing whatsoever to the story except some eye candy.
Fantastic Arousal: Setsuna's wings seem to be very sensitive, and poor Chachamaru can't seem to impress on Negi to wind her up slowly and gently.
Her own damn fault in that she keeps telling him that it feels good and Negi, being only ten, thinks that more is naturally better. Chachamaru ends up talking in a wingdings-like font from the overwhelming pleasure.
Fantastic Racism: Against woodnymphs and other demihumans by humans, who also had no problem cutting horns off them(a bit like real life, the horns, not hunting humans) and selling young girls into slavery.
During the assault on Cosmo Entelechia following their attack on the Governor's Ball, Poyo uses a special artifact to show what Cosmo Entelechia is: Negi is placed in a Lotus-Eater Machine that gives him the happy family he always wanted, though some of his friendships have taken setbacks since it's the ideal possible world for him. The rest of the group apart from Chisame and Makie are shown similar temptations, though we don't see much of them. Negi chooses reality the instant he realizes he's not in it. Spending too much time in such a happy place would make it impossible to leave.
Eva tries to convince Setsuna to give up her swordsmanship in favor of living the life of a normal girl. She also says just focusing on being a bodyguard is fine, but that she can't handle both. Setsuna rejects both choices.
Finger Poke of Doom: Negi manages to stun Sextum briefly with a poke that also removes her clothing before she gets up and is then incapacitated for real by the Gravekeeper, who attacks from behind.
Finger Snap Lighter: When Konoka asks Setsuna about trying out magic, Setsuna reveals she can do this with her own kind of magic.
Finger-Suck Healing: Konoka teases Setsuna once by starting to suck on her fingers and saying it's healing, then laughs and uses magic.
Fire-Forged Friends: Negi and Kotaro start out as enemies in the Kyoto arc, after which Kotaro is arrested offscreen. A few chapters later, he shows up again to help Negi defeat a demon and becomes his rival/friend once they're done.
First Kiss: A lot of the girls on Negi's team have their's with him. Negi himself gave his to Asuna and her's to him.
Almost every person acts very nervous as well, and then came Asakura's turn. Her pactio was the only one to occur off-screen and she was so not nervous about it that she got a commemorative photo for it.
First-Name Basis: In a similar vein, Konoka spends most of her time trying to get Setsuna to call her 'Kono-chan' rather than 'Ojou-sama'. It doesn't work.
Flash Back: Sayo's memories in episode 19, Konoka's in episode 21. In the manga, Asuna also gets many flashbacks related to her mysterious past with Ala Rubra.
The most hilarious take on this trope is when Rakan watches Homura's Flash Back.
Flash Step: A must when fighting professionals. Negi learns it from Kotaro before the Mahora Tournament. You use magic or ki to push off the ground very quickly and then when landing at your destination quickly use the same kind of thing to stop. However, you can be intercepted mid step since it's impossible to change course. Masters can even perform the technique in midair, as seen with Kaede, the Ala Alba master of the move.
A lot of Asuna's abilities and fractured memories are a hint as to her true nature, especially her magic cancel.
The location of the Magic World is suspiciously never mentioned. When the series actually gets to it, we get a few pieces of information from time to time that help point out where it must be. Most importantly, we're given the size of the place (slightly less than one third that of Earth) and the location of features such as Olympus Mons.
Forgot Flanders Could Do That: Given how most adaptations (and the later chapters of the manga) focus more on Konoka being Negi and Asuna's roommate and her relationship with Setsuna, some fans tend to forget that she is also a member of the Library Exploration Club.
Forgotten Phlebotinum: An aversion occurs in the kidnapping plot in the Magical World Arc. The Pactio cards ability to summon the partner to the master. However, it has been mentioned by Chachamaru that the functions of the Pactio Cards are very easily jammed. There is also a distance limitation, which is why Negi couldn't summon his students to him when they were scattered across a planet. It's more of a case of Awesome, but Impractical and Useless Useful Spell. Also, Fate himself also used that function to summon his subordinates just before confronting Negi and kidnapping Asuna.
Formula with a Twist: Negima started as an on-the-fly example of the Harem Genre, albeit with a clear supernatural angle and focusing on a young teacher to a class full of girls. Slowly but surely, it turns more into a Shōnen action series as more of the magical world starts to come to play, and thus his harem becomes a Battle Harem. The reason it's "on-the-fly" example is because the author wasn't really trying to make another harem series and wanted to do a more straightforward shonen series, but seemingly relented because the mangazine he worked for pushed him into it. So he did as they wished but turned it more into the shonen series he wanted to do, killing two birds with one stone.
For Science!: Hakase's justification for peeking into Chachamaru's 'treasured images' folder. Never mind that this effectively meant probing Chachamaru's mind against her will, on the subject of her crush, no less.
Fountain of Youth: The Age Changing Pills can allow someone to look older or younger by several years.
Freudian Excuse: Played with in Eva's case: after recounting the tale of her life, including how she became a vampire and killed her way through the centuries, Asuna's response is immediately "So... it's not your fault, right? Because you didn't choose to be bad?" Eva takes this as more evidence that Asuna is an idiot.
Friendly Rivalry: There's a brief scene where his students joke that Kotaro and Negi call themselves rivals but spell it 'friends,'. It's a joke involving the Japanese writing system.
Friendly Tickle Torture: The class pulls out a bunch of robot hands to do this to Chao during their farewell party in the Festival Arc. They wanted to see tears from her, and if they couldn't get them from emotion, laughter would do just fine.
Friend or Idol Decision: Negi is forced to either stay behind and fight a giant monster so his students can escape with a magical book that can make them smarter (for the big exams) or dump the book so they can all escape safely. Subverted in that Negi ends up trying to stay behind, but Asuna decides to make the "right" choice for him anyway.
Friendship Moment: After her early graduation and before the planned ritual that will put her to sleep for a century, Asuna tells Ayaka that she was the best thing that ever happened to her.
Fugitive Arc: Negi and company go on the lam during the magic world arc.
Full-Frontal Assault: Dynamis, of all people, does this in the final battle. No one saw it coming and no one knows why he did that... (though Takane D. Goodman mentioned earlier that her Shadow-created clothes provide even higher defense with direct skin contact, and Dynamis does use Shadow magic)
Full Moon Silhouette: Near the end of the Kyoto Arc, after Setsuna rescues Konoka from the clutches of the enemy.
Eva has one at the beginning of the Mahora Blackout Operation.
Fun Size: Both Sayo and Setsuna have an absolutely adorable smaller form. Then there's Chachazero, who despite being psychotic can be quite cute.
Functional Magic: Most of the big spells will have enough explanation in-story for the reader to really get a feel as to what's going on and how it works. The appendices in the books give properly scientific and historical explanations for the spells, leaving enough room in the physics for the "it's magic" kind of Willing Suspension of Disbelief. This goes to create a very real-feeling system of magic that creates a link between ancient beliefs and modern scientific understanding, helping to tie the world together as "our world, but with magic".