The rules are simple: Outsmart and kill all the others to become a god.
"What are you scheming?"
"An interesting game."
Mirai Nikki (literally Future Diary) is a dark manga about the asocial Yukiteru Amano, who obsessively keeps journals. One day, he finds that his imaginary friend Deus Ex Machina, the lord of time and space, has made his cell phone diary able to predict the future. After getting over the initial shock of having a supernatural cell phone, Yuki enjoys his newfound powers until he comes across a diary entry stating his exact time of death...After taking out his would-be murderer, Yuki is invited to a gathering with ten other people, where Deus explains that they are now in a Battle Royale for the position of God. Some of the diary holders have personal reasons to claim the throne; others are psychotically insane. And soon enough, young Yuki finds himself without any true friends or allies aside from the curiously Yuki-obsessed participant, Yuno Gasai...The common traits of all twelve diaries are as follows:
All diaries predict the future. Each diary does so in a different fashion, based on how the owner used it before they were selected.
Each owner is assigned a number from 1 to 12, and until their identity is discovered by the other owners, is only referred to by that number, Yukiteru, for example, being called the '1st.'
The diaries can take any shape or form, but the most common by far are cellphones.
Should a diary owner do something differently or influence events so that the results turn out differently from a diary prediction, the diary changes accordingly. In short, the futures set by the diaries are not set in stone.
Most importantly, a diary is its holder's future. If it is damaged beyond working order by whatever or whomever, the diary's owner will cease to exist.
Mirai Nikki also has two spin-off manga. The first is Mirai Nikki: Mosaics, focusing on the ninth diary holder Minene Uryu and expounding on several of the minor characters. The second is an Alternate Timeline spin-off, Mirai Nikki: Paradox, in whichAru Akise replaces Yuki as the main character.The manga was licensed by Tokyopop, and released in the United States as Future Diary; 10 of its 12 volumes were released before the US branch of the company went under. An animated adaptation aired between October 2011 and April 2012 with a pilot OVA released beforehand.A live action drama called Mirai Nikki: Another World began airing in Japan on April 1st, 2012, based in an alternate world featuring a familiar plot but with a new cast of characters. Most are expies of the original characters with some differences. Arata Hoshino takes Yuki's place, a Lazy Bum of a college student who has no interest in his future. That is until he receives a limited release cell phone from his friend Rui Moriguchi which happens to have the Future Diary's powers. Now stuck in his own survival game, with his own version of Yuno for company.A sequel, titled Mirai Nikki Redial, is now in the works.Compare and contrast Death Note, which also features a "notebook" as a centerpiece, although in that case the diary controls the future rather than predicts it. Also compare and contrast Kamen Rider Ryuki which also features a "There Can Be Only One" style royale amongst 13 individuals. See also Devil Survivor, for the counterpart "Laplace Mail".Definitelynot to be confused withYume Nikki, although there may be some connection in there somewhere.
Absurdly Sharp Blade: Yuno is typically armed with a variety of kitchen implements, but the damage she does with them is out of this world.
Abusive Parents: Yuno's parents were originally nice to her, but soon gave her only enough food to barely survive to condition her into an "elite" person and imprisoned her in a small cage at the tiniest infraction. The depths of their insanity are particularly exemplified in how they kept and posted for her view detailed statistics on each such infraction, from talking back to coming in late, which is why she eventually reversed the situation and kept them captive in the cage, waiting for them to turn back into doting parents. They never did, so she never let them out.
It's revealed later on however that her mother was the abusive one while her father wasn't around to stop it making it Parental Neglect in his case. The anime also portrays her mom as being not all there and mentally unstable like Yuno as well.
All There Is To Know About The Crying Game: Actually an in-universe example: since the diaries all give the DEAD END of the user, it forces the user to change tactics in order to avoid it. However, there are unwritten portions that are found within the diary, and, when given the option, the user can take that hidden option, such as when Yukiteru decides to open a suspicious door in Yuno's house that causes every Diary to be rewritten and even surprises Deus.
It's shown that the 3rd world is less of a Crapsack World than the 1st world because all of the events that made the main characters' lives crap and motivated them to turn evil never happened. Almost everybody (including Yuno) lives happy, normal lives.
Note that this is mostly because the game was scrapped once the Mayor read 2ndWorld!Yuki's diary and talked with Deus to forget about it. Since the game, and thus the diary creations did not happen, the 12th, 8th, 7ths and 3rd did not die due to the events that ocurred because of them. The commotion stopped the 6th's parents from dying, which prevented the Ometaka cult from degrading, and consequently prevented the corruption and death of the 5th's parents, which also led to him being a normal person. Minene got Kurusu (the 4th) to check his son ahead of time, so his son was saved, eliminating his reason for his Face Heel Turn IF the diaries had been made. God!Yuno's death ended the struggle, which caused 3rdWorld!Yuno's mother to show she still loved her family. This led to 3rdWorld!Yuno being a normal girl. The rest is inherent to the world however, as Hinata and her father (the 10th) reconciled, Yuki's parents never divorced and thusly, he did not grow up thinking himself a failure. This ostensibly led to him developing the confidence to becoming a couple with his original crush. The only thing that didn't change was that 3rdWorld!Minene was still a terrorist at large.
Aluminum Christmas Trees: "Cell Phone Diaries" are not uncommon at all in Japan, but the practice is nigh-unheard of in the west, leading to the set-up to be a little funky for audiences unfamiliar with the subtler aspects of modern Japanese culture.
Always In Class One: Averted. Yukiteru and Yuno are both in class 2-B initially, and they end up in 2-C and 2-D respectively and their new school. While that can still be considered somewhat lazy, it looks like this was a deliberate aversion.
Attempted Rape: Tsubaki orders her servants to gang rape Yuno, the same way they did to her for years, as a way to draw out Yuki and kill them both. Yuki manages to destroy her diary before anything happens.
This pretty much sums up the majority of the cast, really.
In Chapter 57, there is Mur Mur's true form.
Babies Ever After: The epilogue depicts 3rd World Ai (7th) and 2nd world Minene (9th); the first of which is pregnant and the second of which has two babies... who have apparently inherited part of Deus' power which was in her.
Badass: Yuno without a doubt. Naturally smart and cunning, she's also deadly with just about any weapon from melee weapons to guns; a true armsmaster.
He definitely earned his title of the strongest Non-Diary holder in his Spin-off, Paradox, where in one fell swoop, he seduces the 6th, befriends the 5th, and allies himself with one half of the 7th and one of the 8th's followers, all without use of a diary. This because he got bored of following Yuki's path, and so decided to Screw Destiny.
Later, he obtains a secondary diary from the 8th, allowing him to scry the actions of diary holders and fool their predictions. He ends up losing it in the chapter following its debut, however.
Barbie Doll Anatomy: Averted in Chapter 52 after being played straight for the rest of the series.
In Chapter 54 Minene saves Yuki from falling off a cliff he was climbing.
Big Entrance 12th (Yomotsu Hirasaka) does this when introducing himself to the 1st, 2nd, and Sixth in a manner that imitates the Power Rangers thanks to giant explosions going off in the background, a derranged entrance speech, and a five man group colored in 5 different colors doing a .
Body Horror: If your diary is destroyed, you die in a manner that appears as though a black hole spontaneously generates in your chest. It's much more noticeable in the anime.
Book Ends: In the first chapter, when Yuki almost stabs Yuno, she tells him "You didn't stab me, that's not the future." In the final chapter, Yuno considers stabbing Yuki, but stabs herself instead, saying "I can't stab you, that's not the kind of future it'll be."
Bread, Eggs, Milk, Squick: At the end of chapter 23 when Yuki asks Yuno why she can't leave some luggage. She says she can't because of important things like "underwear, towels, meds, and a bunch of other stuff". The "other stuff" is shown to the viewer as the skeletal heads of her parents.
Hinata's dad is mostly absent from her life due to his obsession with his dogs and disappears altogether when he's killed.
Does This Remind You of Anything?: When Yuno chains Yuki up and feeds him herself, Yuki refuses to eat. It doesn't help that she's in her underwear and sitting on his lap. The following conversation occurs:
Yuki is shown to act this way towards Tsubaki, quickly trusting her and wanting to protect her. Granted, some of this is probably due to the fact that she looked to him like a beautiful Damsel in Distress that is one of the few sane people he had seen recently. Too bad he's very wrong.
Akise is shown to act this way towards Yuki in the Alternate Timeline spin-off Paradox. He just met Yuki, yet quickly decides to use Mur Mur's wish she promised him to save Yuki and comes to the conclusion that he's going to fight in Yuki's place, allowing Yuki to become God.
Distressed Dude: Yukiteru spends the better portion of an entire issue chained to a wall.
Downer Ending: Subverted at the very end. The series ends with Yuno dead and Yukiteru moping about it for 10,000 years, not even bothering trying to recreate his own world. Then you reach the epilogue which goes full reverse into an Earn Your Happy Ending.
Drum Bathing: Near the end, Yukiteru and Yuno take a bath in a oil drum together.
Yuki shares a number of character traits with Shinji, especially in the beginning. Both are timid and lonely but unable to connect with the people around them even if they really want to and forced to fight even though they really don't want to. Both seem to want their father back in their lives, but both end up betrayed. The main difference seems to be that Yuki has his mother and Yuno, the latter being something of a mixed blessing.
Deus himself looks a bit like an Eva in some panels of the manga.
Akise is a close expy of Kaworu from the same series, and the anime gives him the same voice actor. The parallel is at the same time taken further than expected with the revelation that Akise is an Artificial Human created by Deus, just like Kaworu is an Angel, and harshly subverted when Deus denies that Akise's love for Yuki is genuine and an example of Akise's "free will", while it's commonly accepted that Kaworu's love for Shinji, born from his free will, was what made him disobey his orders.
Minene can also be considered as an expy of Misato from Evangelion.
Kurusu seems to be modelled after Kaji in his appearance but his willingness to perform a Face Heel Turn in order to become God for his family , specifically to save his dying son make him more similar to Gendo in personality. 5/6 expies!
Everyone Calls Him "1st": The diary owners are all referred to by the order in which they were given their diaries. Most of the diary holders don't even get any other name most of the time they are mentioned. Particular mention goes to The 10th(not called by his real name until his murder is being investigated) and The 12th(his real name isn't even mentioned until his diary states his death).
Evil All Along: In chapter 50, Akise claims that Yuno is the actual villain, who used Yukiteru, and plans to drive him to the brink of despair and kill him in order for her to become God. Of course, Akise is the one who said it, so who knows if it's actually true. As of chapter 53, it seems that Akise was right and wrong at the same time. Yuno wants to kill him, but only so they can betogether forever via an endless time loop.
Food As Bribe: In the last chapter of Mosaic Akise uses Minene's hunger to get her to compete in a beauty pageant with the incentive that she can use the prize money to buy herself food. He keeps it up by deliberately eating food in front of her as a constant reminder to why she's competing.
Gainax Ending: The epilogue most certainly counts. 1st world Yuno commits suicide because she can't hurt Yuki. This leaves Yuki as God of the 2nd world, only he's so depressed about it he doesn't do anything and lives in a vacuum for 10,000 with only Mur Mur for company. Then Yuno breaks the walls of time and space with a hammer. It turns out 3rd world Yuno inherited 1st world Yuno's memories. Then, 3rd world Deus invites the two to become his successor. Presumably this is because they've both already won the game once each. Both get a Happy End from this.
Played with - despite all appearances, none of the characters believe themselves to be God or have Godlike powers. They are competing for his position, but each has their own, unique, reason for wanting the position and power, very little to do with their ego. Not to say the reasons are good...
Heel Face Door Slam: Remember Yukii's father? The guy that only came back into Yukii's life to steal and then break his cellphone so that his debt will get paid off? Remember how he took Yukii's parachute to escape, leaving his son to die? Remember when he stabbed and murdered his ex-wife to avoid going to the police? Well, he had just spent the entire day praying for forgiveness and buying a telescope to watch the stars with his son. He promises Yukii to turn himself in...right before he gets stabbed in the stomach, while his son watches. Door slam, indeed.
In the Alternate Timeline spin-off Paradox, Akise maintains that he isn't gay - he only feels this way about Yuki. This is also Akise's reason to Screw Destiny in chapter 48 of the main storyline. He states directly to Deus' face that he loves Yuki which is why he meddles with others' plans beyond the will of Deus.
In the main storyline there's Mao, who's not-so-secretly in love with Hinata - she can't stop looking at/thinking about/lusting after/recording in a diary Hinata's impressive bust (for a 14-year-old).
Ironic Echo: In the manga, Minene outs Yukiteru as The First by reading the look in his eyes when she pieces together the clues leading to his identity. Later on, Yukiteru manages to avoid running on one of her landmines by reading her in the same way.
Yukiteru: You said it yourself! The eyes have it! *cue Eye Scream*
Just Hit Him: Double Subverted in chapter 23 of the manga and episode 12 of the anime. After the flash grenade explosion, when Yukiteru and Kurusu regain consciousness, Kurusu grabs Yukiteru and actually starts to beat him up... but then either throws him or lets him fall down, with Yukiteru conveniently landing right next to the dropped gun.
Kill 'em All: In the second world, literally everyone - except Yukiteru (god) and Mur Mur - dies. Even *after* killing every character with a face (except Minene, who bails out to world#3), the world simply ceases to exist. Which by that stage is probably euthenasia. Of course, in world #3, all the characters live happy lives.
Knife Nut: Yuno prefers the ax, but she knows her way around knives too.
Yuno wanted to meet Yuki's mother but she was worried that him mom wouldn't like her. So she brought some tools with her just in case, and by tools she meant a duffel bag filled with knives.
This was more of a subversion or playing with the idea of a Lotus Eater Machine used as Fridge Horror. While the Machine is utilized, Yukiteru is VERY aware he's in one as he's flat out told so and Yuno does nothing to mess with his mind or memories. So it's more like a very pleasant jail in which he can have anything he wants than a true Lotus Eater Machine.
Manipulative Bastard: Happens with almost Death Note-esque frequency. A particularly disturbing mention must be given to Chapter 49. Akise has stabbed Yuno and left her for dead and is trying to reach Yuki before he kills the 8th and Hinata/Mao/Kousaka. Yuno, bleeding to death on the ground, calls Yuki and tells him that her diary told her that they were going to betray and kill him. Yuki, in the middle of a mental breakdown at the time, believes her and shoots Hinata. Yuno, on the other line, starts laughing, while a shot of her diary reveals that Yuki's friends weren't lying. She didn't want them to have him.
Not to mention Juno "the goddess of marrige" which according to the Master Wiki is pronounced "Yuno." Coincidence?
The fact that Juno was the most possessively jealous yandere goddess helps a lot. Also, Yukiteru's own name is a corruption of "Jupiter".
Heck, all the diary holders have names that associate them with some Roman god or goddess.
A Million is a Statistic: The conflict between the diary holders has resulted in a total body count that numbers somewhere in the hundreds. Most of the diary holders have no reservations against killing countless innocent bystanders in pursuit of each other, and even the 1st, Yuki, ends up crossing his moral boundaries.
Moment Killer: Nothing gets in the way of a marriage proposal like learning that the Big Bad has succeeded in his plan when you thought you'd foiled it.
Yuno invariably kills her own moments. Usually by doing something completely insane.
Mood Whiplash: The relationship between Yuki and Yuno constantly and abruptly switches between "Aww aren't they such a cute couple" and "What the hell is wrong with that girl?!"
Moral Dissonance: In the later chapters, Yuki's plans to win the game involve having Yuno murder the 8th's children so they can seize her diary, and later, murder innocent bystanders in order to cause a huge stir and put the 11th and his diary at a disadvantage. Somewhat justified by Yuki's desire to become a god at all costs after having had his parents killed. In his defense, he did keep a list of the people he killed so that he could remember to resurrect them all later. Of course, that would only work if he was truly able to bring them back.
Yuno went from having an appropriately-sized chest for a middle schooler (fairly small in the beginning) to having large breasts in the course of about two chapters.
In one of the last few chapters, she gets her HAPPY END sans censoring.
Minene also gets in on the action occasionally. At one point, the 12th chains her up in her underwear sans bra, with only Godiva Hair to protect her naughty bits. Oh, and she gets a gratuitous Shower Scenewithout censoring twice in the series.
Mummies at the Dinner Table: Yuno keeps her parent's corpses in a cage and talks with them. Later, she chops off their heads and carries them around with her.
Mundane Utility: In the grace period between Yukiteru getting his diary and Deus announcing the game, Yukiteru uses it for things like cheating on a test.
Murder the Hypotenuse: Both Yuno and Akise (in "Paradox") are willing to do this and much more in order to keep Yuki for themselves.
Nay Theist: Minene. Until she became a diary holder she only attacked religious targets, due to losing her parents in a religious struggle as a child. Her attitude comes off as justified, in a Strawman Has a Point kind of way, when you think about it. Her beliefs are basically that if there is a God, he is unworthy of reverence because he is clearly indifferent to human suffering — if not outright malevolent. The whole backstory bekind Mirai Nikki is that Deus, who to all practical purposes is God, considers the best solution to the problem "I'm dying and I need to choose a replacement" to be "pick a dozen deeply deranged and often violent individuals and incite them to kill each other until only one survives, and never mind how many innocent bystanders die along the way!"
Necromantic: Yuki becomes a rare protagonist version after his parents die. He decides to win the game to bring them back to life. It won't work.
Nobody Poops: Subverted in that Yuno mentions taking care of Yuki's "potty breaks" when she kidnaps and holds him hostage and she later has to pee in a corner in front of Yuki while they are hiding out.
Official Couple: Yukiteru/Yuno, Marco/Ai, Nishjima/Minene, & a bit surprisingly, 3rdWorld!Yukiteru/Wakaba. Also, in the anime Kamado Ueshita and John Balks are unambiguously shown to be a couple in the 3rd World.
Once More With Clarity: When Minene was asking for info about how the 11th's diary works. Deus runs his arm through her though it was dismissed as an illusion and was never mentioned again. Later it was revealed that Deus had transferred half of his powers to her to combat a threat which is threatening the flow of the game and makes her forget about it for a while until the right time.
Yuki starts off as this, but then loses it when his parents die.
The 8th is relatively sane. She doesn't have the will to kill. Her children, on the other hand, do. The only reason why the kids are fighting though is because they want to protect the woman who raised them from the other diary holders.
OVA: The manga was given an 8-minute one in September 2010 that rapidly covers the first several chapters.
Personality Powers: Each one of the diaries reads the future in a different way, this as a result that each Diary reflects its Holders, in terms of personality, traits, desires, etc.
The 1st's diary reflects on him being an indifferent,reclusive bystander.
The 10th's diary reflects his obsession with his dogs
The 11th's diary reflects his megalomania as well as his status as the creator of all diaries.
The 12th's diary reflects his justice seeking outlook
The Plan: In a series about dueling future readers with magical diaries, you need to do this to get anything done. Thankfully, due to the... unstable nature of the future(With up to 12 people actively changing and screwing with it), there are no plans which are durable enough to get to the Roulette stage of gambitting.
Plot-Induced Stupidity: Without this, the plot would be stupifyingly complicated. As it is, though, the main character often only checks his diary just before or after an event. Even though it is initially described as being able to see 90 days into the future, it is very rare for anyone to even bother to read more than a little bit ahead. Vaguely justified in that the future is constantly changing whenever any of the diary holders does anything at all while knowing the future, so anything more than the immediate future would be pretty useless.
Please Dump Me: Chapter 56 has Yuno doing everything she can to get Yukiteru to hate her.
Poisonous Friend: Yuno is about as poisonous a friend as her body's volume of plutonium.
Rape as Backstory: Tsubaki. Also Ai and Marco's backstory; he interrupts an attack on Ai.
Reality Writing Book: Mirai Nikki features journals which contain the future entries of characters, allowing them to see what they'll experience in the future, and react to them. The journals change as they do things. Most of these journals take the form of diaries entered into cellphones, though one woman has hers on a scroll.
A blind man and a child have their diaries on a tape recorder and picture book, respectively.
"The Reason You Suck" Speech: Marco gives Yukiteru a healthy dose of this during every encounter they have. He says that Yukii and Yuno will never beat him and Ai simply because Yukii is a coward that let's Yuno fight all of his battles and never gets his own hands dirty. This occurs the first time after they have just knocked Yuno down and right before Mar throws Yuki from a balcony.
Relationship-Salvaging Disaster: A few days after the confinement incident, the attacks of the 7th forces Yuki and Yuno to come back together to beat the 7th. It helps that after this Yuki was convinced by the 7th to reevaluate their relationship and give Yuno an important Armor-Piercing Question about her love for him.
Reset Button Ending: An inversion on the usual good-to-bad, in that the 'second world', in which the story takes place, ends, and they create the 'third world', in which everyone - including most of the diary holders - live happily ever after.
Sadistic Choice: In Chapter 55, Yuno forces one of these on Yuki after they, Minene and Mur Mur jump back in time. Either Yuki hands over the 3rd world's Yuno to be killed, or 1st world Yuno will kill Yuki's parents.
Sakurami Is The Center Of The Universe: Almost every diary holder, who are destined to rule over all of space and reality (and the 6 billion people on this planet in that regard), live in Sakurami.
Justified — Deus Did It. He chose Sakurami because John Balks, its mayor, and 11th Diary Holder, asked him to.
Screw Destiny: These are people with future-predicting diaries fighting to become a god. Of course this is going to happen.
Originally Yukiteru alone was supposed to have this position but due to Yuno keeping him from having free range of movement which prevents him from fullilling his responsibilities . His way of resolving this was to give part of the position to someone else more available and he decided it would be Minene
Self-Made Orphan: Yuno. Subverted by the revelation that she was actually adopted, so it wasn't her biological parents she killed.
Snicket Warning Label: Inverted. The series ends on a downer note with Yuki sulking in a void of nothingness and 2!MurMur reading the same thing for the ten millionth time. 3!Yuno, while now well-adjusted, still feels that there is something missing. The manga lists some credits, and cuts to a black double-page spread. Then comes Future Chapter One - 1!Yuno has managed to sync her memories with 3!Yuno and smashes the time-space continuum open with the Biscuit Hammer, allowing her and Yuki to reunite. 3!Deus decides to not hold a game and instead appoints Yuki and Yuno as the new gods of the third world automatically, and everyone lives more-or-less happily ever after.
Spell My Name with an S: Yuno's nickname for Yuki should be written as "Yukii" if you go off the katakana for it, though Tokyopop writes it as "Yuki" instead. Most scanlations stick to the former.
More notably, the Eleventh's name is romanized as John Balks in most of the scanlations, but Tokyopop romanizes it as John Bacchus.
That cute little girl in the Causality Hall, ムルムル? Most translations and webpages romanize it as "Muru Muru" or "Murumuru", but the opening for the series reads clearly "Mur mur" (in two lines) in the background behind her. Any relation?.
One chapter ends with Yuki looking as if he's going to abandon Yuno when Akise reveals that she's not the real Yuno. Next chapter reveals that he let go of her hand so that he could push to the ground to avoid gunfire from the 11th Diary Holder.
Subverted later in the twin towers when Minene points her gun at Yuki. Turns out there was just a mook behind him. She then explains that she will kill him if the plan fails and nearly does. Ends up truly being double Subverted once she doesn't go through with shooting him and instead helps him to reach 11th.
Stalker with a Crush: Yuno. In one of the more disturbing chapters, right after the hero and audience think she's not so bad, the girl drugs the hero and chains him to a chair. Of course, this is after we learn that she killed her parents.
This series loves playing ping-pong with this trope. The status of it by the end seems to be "Stalking is love, but only because you're as crazy as her now."
In chapter 57, Yuki states that he fell in love with Yuno because "she was always by his side."
Star-Crossed Lovers: Yuki and Yuno will never be together, since one of them needs to die to complete the Survival Game. At the end, Yuno dies to ensure Yuki lives, but her memories are given to her 3rd world self and she becomes god to be with Yuki.
Stealth Insult: Yuno does this during the second fight with Sevenths after recovering her and Yukiteru's diaries. She comments that the diaries that were put on display by Sevenths were obviously fakes and that only an idiot would mistake them for the real ones. Yukiteru's father made that exact mistake moments earlier.
Also when Yuno was fighting Kurusu and his goons in the hospital.
Subverted in the fact that Yuno probably didn't know that the grenade she used was only a flash bang. Nobody ended up dying.
Talking Is a Free Action: Oh, so much. "Yuki! There's a mine 1 meter in front of you! Go to the left!" Doesn't sound ridiculous, until you realize that he's sprinting forward, and Yuno's shouting directions to him. And it's commented that he's a good runner, too.
The anime makes this more believable: "Yuki! To the left! ... Now the right!"
Texting is also a free action. Most of the diary holders have lightning-fast thumbs.
Teens Are Monsters: Apart from the already messed-up protagonists, there is Ai's backstory: some of her female classmates set her up to be raped. For no real reason other than the fact that they didn't like her.
There Are No Adults: Vastly averted. Although the two main characters are school age, others are not, and the school-aged kids' parents end up central to the plot. Read: dead most of the time.
There Are No Therapists: Considering most of, if not all the characters, can be classified as mentally unstable if not out right insane you think half the cast would be in an asylum by now.
There Can Be Only One: God has apparently decided that if he's going to die anyway, he might as well see people fight to the death first. And what better way to chose a successor? Subverted in the end, as 3rd!Deus permits both 2nd!Yukiteru and 3rd!Yuno to succeed him.
Akise crosses into this when he kisses Yukiteru in front of Yuno to get her to attack him.
Well to be fair about Akise no one but Murmur and Yuno knew she had a second diary.
Too Soon: Tokyopop changed the name of the Twin Towers to "The Double Tower Building" in volume 9. It doesn't help that it is attacked by the series' resident terrorist bomber.
The anime sidesteps this by adding more towers and renames it the Quad towers.
Took a Level in Badass: After his father is killed, Yuki retaliated against his would-be assassins using the knife which took his father's life, his darts and blocking gunfire directed at him by using a meat shield (another one of his would-be assassins.
Yuno takes a level during the fight with the 7th, when Yuki's praise gives her the motivation to block half a dozen thrown knives in an instant.
Tsundere: Mur Mur pegs Minene as one as she watches the Dating Catwoman antics between her and Nishijima. While Minene insists that she's not going to follow some "shojo manga formula", she can't seem to shake Nishijima off of her, culminating with him proposing, getting her uncharacteristically flustered.
At chapter 56, Yuno's feelings for the 2nd world Yukki are very confusing, so she plays this trope with her unique style:
Yuki calls Yuno on her claim that she locked and chained him up in her room and tried to kill his friends because she loved him.
In Chapter 50, Kousaka calls out Yuki on his cowardly decision to kill all of his friends rather than face the Awful Truth they were trying to tell him. He is later called out on this again, this time by Yuno of all people. This time it sinks in.
Also, Tsubaki becomes one of these when her tragic past in revealed.
"World of Cardboard" Speech: Yuki gives one of these speeches to Yuno, telling her he loves her and that she is irreplaceable to him. He vows to save her, all while climbing up a sheer cliff with his bare hands.
In case we haven't hammered it home that Yuno is the mascot of this trope, its now become a rather large trend to copy other characters, Yandere or not, onto Yuno's face from the first episode in the anime. You probably know at as 'The Yandere Face.' meme. They sell posters of her making said face at some Hot Topics, even though the anime never got a dub and just finished airing. Poster girl indeed.
The anime includes some parts of the Mosaic spin-off.
The 3rd also got a bit more screentime to better illustrate his presence in the first episode.
Some things from the manga are reworked to make more sense (such as averting the Talking Is a Free Action described above, and changing a room filling up with concrete into a room filling with gas)
Some content is added between scenes from the manga (such as Yukiteru's futile attempts to inform Kurusu about the dead bodies in Yuno's house.)
In the anime adaptation of Yukiteru's and Yuno's second battle with 7th there is an added scene of Yukiteru's father asking Yukiteru to give him his cellphone and promising to buy him a new one after his debts are erased, indicating that he didn't know that breaking the phone would kill Yukiteru. In the manga it wasn't made clear whether he knew this or not.
Also expanded is the 7th's past together, with a story from their high school days, leading to Rape as Backstory for Ai and Interrupted Suicide for Marco. It also adds more to Marco's reason for not leaving Ai in the tower, despite him also being injured.
The anime also expands on Yuno's family situation and the reason why her mother's depression led her to take such abusive measures. Apparently Saika felt she couldn't fulfill her role as a wife to her husband for being unable to conceive a child, and felt neglected herself as she had trouble dealing with his long work hours and business trips. He also either missed or ignored her phone calls to him while he was away. Coupled with this was the fact that she also felt like a terrible mother to her adoptive daughter as well; she believed that neither of them loved her or wanted her in their lives. She demanded so much of herself that she started pushing equally high demands on Yuno as well, taking out her own feelings of inadequacy on Yuno in the form of abuse.
The time spent in the third world in general, from the other characters' lives to the fight scenes between the last survivors of the second world, is expanded upon.
Altum Videtur: The opening features a rapid firing-off of the names of the Dii Consentes, the twelve Roman gods and goddesses that were considered to be the highest deities. In the manga, the twelve diary holders (each already a potential god) are named and themed after one of the gods with Bacchus added and Neptune replaced with Pluto (then again, Minene Uryuu also references Neptune).
Art Shift: Weirdly done with some Medium Blending at the end of episode five in Mur Mur's ending segment with the 12th; the art is suddenly some crudely made clay figures in stop-motion, with some slightly bizarre 2D animation spliced in between. It's because #12 is blind.
Bland Name Product: Kousaka's phone, which is shaped like and obviously is an iPhone, is apparently an iBone.
In a scene where Yuki is buying drinks, he attempts to get some Dr. Papper.
Censor Shadow: A fairly obvious one once Yuno starts smashing heads in the fourth episode.
There's also censor steam in episode 20 when Minene showers.
Conspicuous CG: So far, a two-second appearance in the opening credits is pretty much the only time Deus has used hand-drawn art. There are some bits of architecture and a few objects in the opening credits as well.
The ferris wheel scene in episode 3 switches jarringly from CGI to traditional animation depending on whether the audience is viewing the car from the outside or inside.
10th's dogs are CG in several shots.
Episode 19 also has CG cars.
Death Is Cheap: The Stinger for the first episode has Mur Mur attempt to deliver the 3rd's diary, only for him to err on the side of caution and destroy a phone that seems to be monitoring his criminal activites in painstaking detail before she can properly explain the natures of the diary or the game. This happens several times and she rewinds time to reverse his death every time.
Depending on the Artist: The anime features a noticeable different artstyle than the manga's, the characters look slightly older than their manga counterparts, also many expressions taken directly from the manga are more extreme: Yuno's shots in particular got a tad more lustful towards Yukiteru, and crazier towards everyone else.
Early-Bird Cameo: The anime shows The Third carrying out one of his murders and teaching Yuki and Yuno's class before the point at which he was originally introduced in the manga. Minene also shows up early in her disguise from Mosaic.
Gainaxing: There's a lot of attention paid to Yuno's chest in Episode 3.
If Jesus Then Aliens: When Mur Mur tells Reisuke that he's been chosen for a Future Diary, Reisuke says to her "If there's a God, it's not strange for there to be aliens, right?" and refuses to participate in the game until she shows him an alien.
Lethal Chef: In the first Stinger of the anime not taken from the manga, Murmur manages to send Yukiteru and his mother to the hospital with her miso soup.
Spoiler Opening: Strongly so, but at the same time it's very vague and you might only see the importance on hindsight. Yuno killing a copy of herself and then the two joining hints at her origin in this world. The first opening also foreshadows every diary owner, shown in shadow with a sequence of items relating to each one.
The second opening is also very much a Spoiler Opening, but for a slightly different reason: Faylan's lyrics are absolutely filled with huge spoilers of the story.
And anything colored blue (after the title drop) in the second opening is destined to die/cease to exist. It includes all the diary owners except First, Second and Ninth, Yukiteru's four friends, explosion flames that represent Ninth's terrorism, and the candle flames that represent the Eighth's foster children. By contrast, Ninth is grey-colored, Yuno has her hair tinted with real color, and Yukiteru who is the nominal winner, is the only fully colored one at all.
Also, the final scene of the anime after the credits, which leaves the whole ending rather ambiguous. Rather than include the whole epilogue where Yuno manages to break through the wall of space-time to see Yukiteru, the last message on Yukiteru's phone changes from "Yuno died." to "Yuno came to see me." This is followed by an announcement of another new project for Mirai Nikki, so who knows what they're planning on now. This can be seen as keeping the spirit of the final pages of the manga, which is described as not part of the series proper but rather a new chapter, making this more or less a cliffhanger.
Expy: Most of the characters are expies of the manga cast, most notably Yuno is pretty much the same characters minus the pink hair and now nineteen.
Averted in Arata's case. He is meant to be like Yuki, but actually has friends, is very apathetic, takes a surprising interest in Yuno and takes a stand against the serial killer.
Heroic Sacrifice: Arata's father Kurou, a fellow diary holder, is stabbed by the serial killer, to save him son.
Insane Troll Logic: Kurou's diary shows him that his wife would be killed by a burglar soon. So what does he do to save her life? DIVORCE HER AND ABANDON HIS FAMILY! Instead of, say, just telling her to stay inside the house that night. That'd have been too easy.