Lt. Col. Hughes is promoted two ranks to Brigadier General and stays a mostly important part of the story. However, he is promoted posthumously, and instead of being a major character he becomes a major plot point.
Colonel Mustang is also promoted to full General by the end of the series (his epaulets have three stars in the photograph).
Subverted in also in that even though Ed ranks up from a civilian to a major within the story, it happens in the instant when he signs the state alchemist contract, and he is not often shown to have any authority (in fact he openly states in one scene that his becoming a state alchemist had nothing to do with wanting power over others). Plus he is never called "Major Elric", he is addressed as "Mr. Elric" as though he was a civilian.
Rant Inducing Slight: Using words like "short" around Ed, even when not talking to him or about him, causes him to go ballistic, with a line like "WHO ARE YOU CALLING A (blown out of proportion version of what was actually said)?!?!" And yes, the caps are necessary. In the 5th Lab, he even does it to himself. (He mentions that maybe being short isn't such a bad thing, and then yells "...I just called myself a tiny little pipsqueak!!!)
Rasputinian Death: Most of the homunculi killed. Wrath in particular took a ridiculous amount of effort to kill.
Scar's eyes are played with: Scar is definitely no one to mess with, the red eyes are an ethnic trait, not Uh-Oh Eyes.
Further played with in one episode of the anime. During Scar's Flashback of the Ishvalan Rebellion, everything's black and white except for the Amestrian soldiers' blue eyes and the Ishvalans' red eyes. Later in the same episode, Scar mistakenly takes warning on them and kills the Rockbells after recognizing them as Amestrians by the eyes.
And an anime-exclusive scene (which happened in the manga, it just wasn't shown) has the soldier Envy turned into change from blue eyes to red just before shooting a little kid and starting the war.
The Homunculi's eyes are shown as round and red when they really start getting dangerous. The fourth ending even plays with this.
Also, Kimblee's eyes turn evil red as he attacks Scar's family in the Ishval flashback, and later on when fighting against Ed, when he reveals he still has a Philosopher's Stone in his possession.
One of a few subtle indicators that tell the audience that Greed is in control of Ling's body is that his eyes turn a purplish-red color, whereas they're usually a bluish-black when Ling's in control. This isn't consistent however, especially when Ling and Greed start to more regularly switch off control.
Al is a subversion, since his armor body has slightly red eyes. This is much more prominent when he uses a Philosopher's Stone.
Red Herring: Hohenheim and Father look similar, and the latter is shown getting off his throne and walking somewhere a little while before the former returns to his home and gives Edward a Breaking Speech.
Mustang and his forces use the order to kill Bradley's wife and the blowing up of Bradley's train as evidence that the Central Senior Command was trying to stage a coup against the Fuhrer, when in fact Mustang was himself the one staging the coup
One of Havoc's two guns stovepipes in chapter 37 of the manga, thus allowing Riza to jump into action. He is not shown throwing away the jammed gun, but we can assume he did, since he only carries one afterwards.
In Brotherhood, a spent round gets stuck in Riza's pistol when she is fighting the leftover Fuhrer candidates, thus enabling her enemies to capture her. (In the manga, she merely runs out of ammo). It actually made sense in this case, because the fight was at such close range that she didn't have time to clear the jam before she had a sword at her throat.
Retraux: The flashback to Ed and Al throwing Yoki out of Youswell is presented as a silent film.
The Reveal: In the film Fullmetal Alchemist: The Sacred Star of Milos, is revealed that the whole city is a giant, tridimensional transmutation circle designed to create a Philosopher's Stone.
Subverted for those Genre Savvy enough to recognize the circular shape of Table City.
The fact that Ashleigh, Julia's brother, isn't really his brother. Or is He?.
Foreshadowing from the beginning, and during the whole movie, since you always can seeMelvin/Atlas' scars.
A savvy viewer may also notice Colonel Herschel's disfigured face, which can be seen even when he's wearing his mask, through the eyeholes and mouth. If one picks up on both this and Melvin/Atlas's scars, most of the critical plot twists in the story can be worked out.
Reverse Mole: When Zampano calls Envy to let him know of Marcoh's location. It turns out he did this at Marcoh's request, to lead Envy into a trap.
The Armstrongs are loaded, being aristocracy and all. They seriously consider buying some elephants as souvenirs.
Although there are jokes about him being a cheapskate, Edward has a seemingly bottomless State Alchemist's "research budget", meaning that money is not an issue for the brothers' constant train journeys and hotel stays, automail repairs, and paying off Ling's astronomical room service bills.
Roy also throws money around casually, paying his female informants well, carrying enough on him to buy a flower seller's entire stock and swanning around in expensive-looking suits. It would seem that being a State Alchemist is a pretty sweet deal, financially.
Rousseau Was Right: Possibly a theme most of the time, although it definitely wasn't in the first anime.
Rules of Orphan Economics: While not technically orphans, Ed and Al are left on their own. They inherited a nest egg from their mother, get taken in by Pinako, and Ed makes a nice living once he becomes a state alchemist, so money is never a problem.
Save the Villain: Subverted when the others stop Roy from killing Envy, not because they want Envy to live, but because they don't want Roy to give in to his anger. They just plan to kill Envy themselves.
Schizo Tech: The world mixes 1920s tech with alchemy and cybernetic limbs.
The carbon fiber in the cold-weather automail is something that shouldn't be within the technological capabilities of a roughly 20s-era civilization. A lot of the Briggs-developed tech falls into this as well. The tank, for example, is of a design that does not look like anything we had in the 20s but resembles post-WW2 tanks. On the other hand, despite their mechanical advancements there do not appear to be any sort of aircraft.
The main power of an alchemist is that they can force almost any chemical reaction and rearrange things on the molecular level. Technology like carbon fiber would be really easy if you could rearrange the atoms individually. There are a lot of materials today that are awesome, or would be, but are extraordinarily expensive or impossible with current technology.
Hohenheim, when he realizes he has become immortal.
Scar, when he sees that the Ishvalan capital is completely destroyed.
Al, when Gluttony swallows Ed and Ling.
Secret Test of Character: It took two years, more pain and anguish than any other pair could take, the loss of their mother, the loss of their bodies, and the loss of each other for Ed to find his answer. And finally, after all the fighting and struggling, the Truth of the Universe accepts Ed's final sacrifice, smiles and says:
Truth: Good answer.
Self-Inflicted Hell: The Truth invokes this as an ironic punishment as payment for trying to play God. Specifically:
Ed tried to rebuild his family, and loses the leg he stood on and his remaining family as payment.
Al wanted to feel his mother's warmth again, and lost his body and ability to physically feel.
Izumi tries to revive her stillborn baby, and loses her reproductive system.
Since Mustang held a strong vision for Amestris, he loses his sight and the ability to see what will become of his country.
Finally subverted when Ed tries to bring back Al again in the finale; since Ed offers his physical ability to perform alchemy, denying himself his life specialty and the ability to bring back the dead (as he did with Al), The Truth sees Ed has learned his lesson and gave a large offering, and allows Al's body to return.
Sensor Character: Xingese warriors like Lan Fan have the ability to detect the Qi of others. Lan Fan can detect the homunculi because of their twisted life energy.
Servile Snarker: Variation with Riza's occasional tendency to yell at her 'boss'. "WHY DID YOU SHOW UP?! ARE YOU SOME KIND OF AN IDIOT?"Played for Laughs, especially because Roy shakes it off; if anyone else yelled at him that way, it's doubtful he would be so calm, but he is No Badass to His Valet.
Shaggy Dog Story: The Sacred Star of Milos. It occurs in some ambiguous (potentially plot-hole-inducing) place in the timeline of the series and conveniently leaves Ed and Al no closer to their goal of restoring their bodies. Star IS a philosopher's stone but it gets destroyed/used up by the end of the film. Since the film takes place in Milos and Table City, far from the main plot, it has no impact on Father's plan. Within the film itself, Milos declares independence from both Amestris and Creta which would suggest some measure of change in the status quo, but since it's a tiny city-state sandwiched between two major military powers (which are explicitly stated to be mobilizing forces in retaliation), their freedom probably won't last. Especially considering Milos' military forces consists of a guerrilla terrorist group, the only chance in hell it has to survive is if the main FMA plot wraps up before either Amestris or Creta decide to quell the insurrection.
A number of said shippers were also put off when the Brotherhood anime watered down some of the Ship Tease. Winry teasing Al about missing May when she initially had to leave was cut, and Roy and Riza's Battle Couple moment near the finale was changed from Roy and Riza leaning on each other as Riza directed Roy's attacks to Riza just standing behind Roy giving directions.
Shipper on Deck: For a series where romance is downplayed in favor of story, there seem to be a LOT of in-universe shippers. In fact, most of that Ship Tease seems to be coming from other characters.
Ed has a tendency to tear his shirt in order to show off his arm (and his abs), not that anyone minds.
Ling loses his jacket-thing and goes around shirtless for a while (yay!).
Roy, when he kills Lust.
Father, when he reverts to his younger form.
Shooting Superman: Although shooting Homunculi isn't completely useless, since they do have a limited amount of times they can regenerate, most of the people shooting them have no idea of this. So, from their perspective, it may just be better to run away.
Ed references The Fly as an example of transmuting people, with a person and a fly becoming a fly-man. Even if that was solely in the realm of movies, it gave Ed the inspiration to try human transmutation.
At one point, Kimblee says "the life force is strong with you."
There are many references to historical alchemists, their beliefs and practices littered throughout the manga.
The scene in Gluttony's stomach where Ed boils a shoe into food is likely a reference to the Charlie Chaplin film The Gold Rush—Ed refers to getting the idea from a film he saw. How Ed and Al are familiar with movies from this world (not to mention made AFTER their time) raises some questions....
Boiling boots to eat the leather was common practice in desperate times of warfare. Being as they are from a war-like nation, it can be rationalized that knowledge of such practices have crept into popular culture.
The mannequin soldiers are very similar in nature and looks to the mass-production Evangelion.
Another possibly coincidental example: during Edward's fight with Kimblee, he slashes his right transmutation circle. That circle contains a triangle which contains a circle. The slash wound divides the circle in two exact halves. A line, a circle, and a triangle - where we saw it before?.
We are repeatedly shown instances of Ed experiencing tremendous pain in his automail and becoming nauseated, sometimes to the point of being violently ill, when there are severe changes in barometric pressure. This is Truth in Television for people in the real world who have metal body parts. Ed suffers the symptoms to a greater extent than most because almost half his entire body is metal, but the nature of the suffering is very accurate.
Roy Mustang uses his gloves to create fire. It doesn't work on rainy days, but if he's a closed-off area with enough water, he can just separate the water into hydrogen and oxygen and use a source of sparks to ignite it. He can't do it in the rain because it's too open, and separating the molecules would endanger everyone around him. Also, the snapping sound he makes is the gases reacting, not the sound of him actually snapping his fingers.
Additionally, Wrath's dying moments amount to this when Lan Fan confronts him. Telling somebody whose grandfather you just killed that you have no regrets and then dying with a smile on your face is a pretty devastating response.
Hughes: Not just my daughter! *sparkle* I'm proud of my wife too!!
At times, Sig and Izumi.
Lust and Havoc in the omake comics.
Simplified Spellcasting: Those who can perform alchemy by clapping (i.e. Ed, Al, Izumi, Roy), and those who have a circle at the ready, such as on a glove or tattooed onto one's body. This allows for a specialized alchemical technique to be at the ready without having to draw a circle.
Slasher Smile: Envy and Kimblee do this a lot. Riza, in chapter 94, to great effect. Also Roy came pretty close on one panel in ch. 95.
Sliding Scale of Idealism Versus Cynicism: Quite idealistic on the whole; but the darker side of humanity is also depicted on more than one occasion. Contrast with the first anime, which is a lot more cynical.
Slipknot Ponytail: Hawkeye during her showdown with Envy. Actually rather justified, since her hair was in a clip which sprang open while Envy was throwing her around the catacombs.
Social Darwinist: A heroic example with Olivier Armstrong and everyone at Briggs.
Riza/Liza/Lisa/Risa (and her using the Code Name "Elizabeth" doesn't help)
Ranfun/Ran Fan/RanFan/Lan Fan/too tempting to write "l'enfant"
Roze/Rose with or without an acute accent
This is not helped by the manga and anime using different official spelling: Lin (manga)/Ling (anime), Ranfan (manga)/Lan Fan (anime), Who (manga)/Fu (anime), Reole (manga)/ Liore (anime).
In the official manga alone the spellings change constantly. The two that change the most are Ling and Ishval. One page of the manga has Ling's name tag bracelets say "LING YAO" but the jail guard in the next panel saying "So your name's Lin Yao, huh?".
Ed does a pretty spectacular one after Hawkeye suggests that he's in love with Winry. Poor Hayate gets soaked too.
Riza: Amusing. He's weak to direct hits.
Prior to that, in Brotherhood, he scores a hilarious one when they first discover Ling in Rush Valley's streets.
Spoiler Opening: Quite a few, but the majority of them would only be obvious to the people who know the story beforehand.
The appearance of a young Hohenheim in the first opening. But he looks incredibly like Ed, so most people don't realize who it really is.
Also Greedling and Sloth make an appearance alongside Wrath, Gluttony and Envy in the third opening sequence, "Golden Time Lover," before they actually debut in the series. Admittedly Sloth isn't that big a reveal, most people would just go "who's that big guy? Oh, so that's what Sloth's gonna look like." But Ling being there is a big damn spoiler, as all it takes is putting two and two together to realize Ling's gonna become a Homunculus.
However, it should be noted that "Golden Time Lover" debuts only an episode before Ling becomes Greed, so it's not too much of a spoiler when you really look at the big picture.
As early as this opening, they show Kimblee tipping his hat in farewell surrounded by a red typhoon of souls—which is EXACTLY what happens near the end.
The fourth opening spoils Greedling's defection and shows him fighting Wrath.
This opening also spoils the Alkahestric Reverse Circle.
The fifth one spoils Roy's blindness and being the last sacrifice, Father's One-Winged Angel form, and the nationwide circle activating. And the last one, it spoils hard.
The reason the spoiler openings aren't such a huge deal is because the things that do happen are indistinguishable from the many things that don't happen so you can never tell without knowing in advance.
Not to mention some of the sequences are completely vague and can be interpreted as metaphors to the things happening at the point in the plot.
Spontaneous Weapon Creation: Alchemists can transmute weapons using the mass of floors or walls, although not many ever actually do so.
Standard Female Grab Area: When a thief steals Ed's watch, they spend most of a chapter chasing her through the city. She vaults over walls and bounces off pillars Ed throws up, and when Al transmutes the ground around her into a birdcage, she just kicks her way out. She's stopped by Winry grabbing her wrist.
The Stinger: These cruelly start showing up occasionally partway into the anime, starting at episode 28. They are often plot-relevant, and if you miss The Stinger you may wind up very confused at the beginning of the next episode.
Ed, who got away with the loss of just an arm and a leg while Al lost his whole body.
Just about ANY person who was involved in the Ishvalan war and isn't one of the bad guys. Especially Roy, Riza, Alex, and Marcoh.
Hohenheim, who is partially responsible for the genocide of an entire race of people.
Sympathy for the Devil: The 4-Koma Theater clip "The Cursed House" portrays Shou Tucker as being driven to transmutation from his wife's unrealistic expectations of what he, as an alchemist, can do for her, which ultimately ends up with her trying to slip wolfsbane into his food. This is seen to take place before Shou transmutes Nina and Alexander, so Shou doesn't end up redeeming himself.
Al: Hey, why are you saying there are only two options? It's strange to think that only one of those can be granted. Why don't you consider the possibility of getting our bodies back, and at the same time, saving everyone? I think that in order for humanity to progress, we must seek a possibility without being bound by principles. Kimblee: Then you should prepare for another possibility. The possibility of you two not getting your bodies back, and not being able to save anyone either.
In Chapter 108, Ed is faced with the dilemma of using a Philospher's Stone to bring Al back (something he's promised never to do), or allowing Hohenheim to sacrifice himself. Ed instead decides to sacrifice his ability to perform alchemy.
Take Care of the Kids: As seen in a flashback, Master Hawkeye's dying words to Roy urge him to "take care of my daughter."
Talking the Monster to Death: Played unusually: When this happens to Envy it's both after he'd already had been beaten in combat and done completely by accident.
Tele-Frag: When Edward gets his arm back, while not explicitly pointed out, you can see a few parts of the broken automail sticking out around his shoulder. One can assume that they had to be surgically removed afterwards.
Telepathy: Ed tries using Al's arm after being eaten by Gluttony for Rule of Funny to contact him. The omake expands on who was contacted.
Scar threw away his name after survivng the genocide of Ishval and declaring himself on a personal war against state alchemists.
The two homunculi who were once human, the second Greed (Ling) and Wrath (Bradley). Several times Ed calls out "Ling" when encountering "Greed" and Greed answers back "It's Greed." Bradley was actually a Tykebomb who doesn't even remember (or care about) his real name, and stopped being human a long time ago.
The thing with Greed and Ling has more to do with the fact that they have two personalities with one controlling the body. It takes a while for them to start working together. The reason that Greed identifies himself is less a case of Insistent Terminology and more to clarify which is the currently dominant personality.
Theme Naming: The homunculi are each named after one of the Seven Deadly Sins. Most of the military characters are named after weapons, vehicles, and companies from World War II.
Human transmutation—arguably the Central Theme of the whole series.
The creation of Philosopher's Stones.
Marcoh: My research is the work of the Devil. And it can only lead straight to Hell.
Those Two Guys: Maria Ross and Denny Brosh, though not nearly as much in Brotherhood as in the first anime.
Thou Shalt Not Kill: Ed, who gets a lot of flak for it because he's in the military. (Though a few of his detractors admit they felt the same way at his age.) Also, during the final battle, Roy's squad use this policy against fellow soldiers.
Al, once he gains the same transmutation ability as Ed.
Falman, despite being on the verge of wetting himself, refused to get out of King Bradley's way during the battle at Central HQ. Now put yourself in his shoes and dare say you wouldn't get out of there screaming like an infant child.
Training from Hell: Ed and Al had to survive on an island for 6 weeks during their training with Izumi, while Izumi herself was left to survive in the arctic with nothing but a knife for 6 months. She's actually going easy on them!
Hawkeye: (to Envy disguised as Mustang) When we're alone together the Colonel always calls me 'Riza.' Envy: You two are together!? Hawkeye: Just kidding. Envy:Crap Hawkeye: Thanks for falling for it. Now do me another favor and die.
Trickster: The homunculi, especially Envy. Father was one back when he was confined to a test tube.
Try Not to Die: Mustang gives this as his only order to his subordinates before they storm the capital.
Tsundere: Winry and Izumi. Winry is type B, which means she's normally 'dere' but can get 'tsun' when someone annoys her (often Ed). Izumi is type A as she seems to be 'tsun' when not putting up a "sweet housewife" front, but is unbelievably 'dere' with her husband.
Understatement: While in Gluttony's stomach and having met up with Envy, Ling comments to Ed that based on his footprint size in the previous fight, Envy "might be a little bit bigger than he looks." Cue the transformation into the giant monster. (Ed has managed to destroy smaller buildings.)
Unfinished, Untested, Used Anyway: The activation of doll soldiers. The villains are losing, so the military decides to use them, and scientists warn him that the tests aren't done yet. However, he ignores the warning, activates them and both get killed.
Un-Sorcerer: Edward eventually gives up his ability to perform alchemy in order to bring Al's body back.
Unstoppable Rage: Subverted when Riza goes into one when she thinks Lust kills Roy but it only puts her further in danger. Played straight when Roy finds out Envy was the one who killed Hughes; he completely curbstomps Envy, and it takes his teammates to stop him.
When Al sacrifices his soul so that Ed can get his arm back, Ed goes extremely berserk on Father...and HOW!
"Get up, you novice! It's time you learned why you're not in our league!"
Unwitting Instigator of Doom: Poor Hohenheim had no idea what helping his little 'friend' in the flask would lead to... which happened to be the destruction of his country and everyone in it, and a centuries' old conspiracy which required the deaths of untold millions of people.
Vehicular Theme Naming: A majority of the military characters are named after World War II military vehicles. Armstrong, Mustang, Hawkeye, Hayate, Bradley, etc.
Villain Decay: Envy starts out being manipulative, clever, and competent enough to be an infiltrator. Then xe gets soundly beaten by Marcoh and May, gets xer power back, and gets curb stomped by Roy. By this point Envy is portrayed as barely smarter than Gluttony and can't even land one blow.
Somewhat Justified — Envy's primary skills are disguise and manipulation. Against someone who's not falling for xer tricks, xe has only xer combat abilities, which are definitely outclassed by the main characters.
The Villain Makes the Plot: All of the protagonists begin the story pursuing their own goals for reasons that don't really have to do with the villains (Get their bodies back, overthrow the government, find the secret of immortality to become emperor of Xing, etc.) but their actions actually help Father's centuries-old plan. Once they start to encounter it, they're forced to redirect their efforts to simply stopping it.
Villain over for Dinner: Bradley/Wrath, finally fed up with the actions of the Elric brothers and company after having ignored it for the most part, sits down to have a nice chat with Winry in order to bring her up as a weakness against Edward later (granted, they didn't know about the whole Wrath business yet at that point in time; but when it's brought up again as a threat they have learned of the secret, so the effect of the trope remains the same). Couple of episodes down the line, Edward and Al are caught chatting with Bradley's wife and Selim for an interesting twist.
Voice of the Legion: Envy, Pride, and Father all get this in their true forms. It actually sounds like a simple reverb effect most of the time, with the exception of that one highly disconcerting occasion where Father laughs out of sync.
Voices Are Mental: Whatever voice comes out of Greedling's mouth will belong to whichever of the two is in control.
Ed: Equivalent exchange. I'll give you half my life... So give me half of yours!
Winry: You really are dumb. You want half? I'll give you all of it.
A Japanese newspaper ran a contest to find the best words to use to propose marriage, and the above quote won. How's that for a Moment Of Awesome? (Never mind the fact that it was subsequently disqualified when the judges found out it wasn't written by the person who entered it.) Han Solo and Westley would be proud, Ed.
Alex Armstrong, with the added bonus of being so cartoonishly overmuscled that it's practically Fan Disservice.
Ed appears to be unable to so much as walk within ten feet of a bladed object without his shirt dissolving to show off the sort of physique girls dream about.
There was also the scene when Mustang came to kill Lust. He was shirtless but wearing his coat, which was completely open and revealing his Mr. Fanservice chest and abs.
War Is Hell: If there's ever been a manga that did a good job of showing what a war can really be like (alchemists aside), this is it.
Wham Arc: All manga chapters following chapter 99 may cause screaming, ranting, stress, crying, irritation, cursing, shock, headaches, nausea and lack of sleep. Read at your own risk/discretion—especially chapter 104 which has caused all of the above. You Have Been Warned.
Sheska never appears beyond the early parts of the storyline, even though other early characters such as Nina and Yoki reoccur.
The scene where Winry gives Ed her earrings has no follow-up.
What If?: In a gag comic at the end of volume 20, Ed starts a long string of "What Ifs":
Ed: The reason I failed last volume was because I didn't think to myself, "What if Kimblee has another philosopher's stone?" So from now on, I need to think about all the "what ifs" in the world, and live more cautiously!
Al: Wow, big brother! Very wise!
Ed: What if I hit my head on the doorway? What if I get my precious antenna caught in the door-jamb?
Ed: What if I grow 30 cm while I'm asleep? What if I can't fit into any of my clothes that following morning? What if no one recognizes me because I'm so tall?
Ed: What if all the women in the world won't leave me alone because of my height, large income and deep intellect? What if they all start fighting one another over me? What if I incite a national emergency? Oh no ... [Type: Gundam, Close Combat]
Don't avert your eyes from death. Look straight ahead. Look squarely at the people you're killing. And don't forget them. Never... forget them. Because they won't forget you''.
Wishful Projection: May hears about the Fullmetal Alchemist from various people, and forms a mental image of a tall, gentlemanly prince... and is horrified to find the short, rude reality. She later forms a similar image of Al's real body, after Alphonse, offended that she would think him similar to his brother, provides an exaggerated opinion of his own traits.
Al's confrontation with Kimblee and Pride involves one being given to him, then he gives one of his own. First, he and Heinkel are pretty much screwed, when Heinkel urges him to use a Philosopher's Stone to win, with the reason being that while he would never do such a thing for selfish reasons, there's no reason why he can't do it to save others. He also tells him that to use up the souls in the Philosopher's Stone would also let the people it consumed fight, through Alphonse, which is what they would want. Partway through, Kimblee asks him why not use the Stone to get his body back and leave everyone else behind, saying that one will cost the other, per Equivalent Exchange. Alphone's response is that it's not two choices, he can and will to do both.
Edward: I'm gonna kick her butt!! Alphonse: Kick her butt? I mean, if it was a guy that would be one thing, but...You're gonna beat up a girl? Edward: I'm not sexist!
Greed plays it straight.
He first tries this on Izumi, and is immediately shown why it's an awful idea, as Izumi proceeds to figure out how to break his Ultimate Shield — which took Ed a whole fight and a lot of injury — and Curb Stomp him in about two seconds.
When they rebel against the military, Mustang and co. avoid fatally wounding any of the soldiers going after them. Subverted by Olivier and her subordinates.
This is also subverted by Mustang's crew as a sort of psychological warfare. Leaving the men alive showed how easy it was for them and served as a way to mock the superior officers, thereby making them angry and clumsy.
Grumman, given an estimated two hours or so of thinking time, manages to turn the situation of the Fuhrer President himself overseeing the annual training exercises into a situation he simply cannot walk away from without a victory. He does this by leaking information about a planned attack on Central. If the Fuhrer stays, Central is defenseless. If he leaves, Central is defenseless and Bradley gets dropped down a ravine by a well-placed train bomb. Bradley being who he is, though, his exit from the story wasn't permanent. Still a very impressive feat, though.
Hohenheim's Umbral Circle failsafe. In the event that Father succeeds in transmuting the entire nation into a massive Philosopher's Stone, minutes later the eclipse's umbra would align with crests made from the lucid and cooperative souls from Hohenheim's own internal stone all willing to make a Heroic Sacrifice, undoing Father's dive once more over the Moral Event Horizon and leaving Father unable to effectively contain the Truth. Who's the Unwitting Pawnnow, ya little Slasher-Smiling gas cloud?
The blood crest for the country-sized transmutation circle at Fort Briggs. Our Heroes find that the base seems to be the location for one, so they're concerned there'll be a bloody mess amongst the ranks. Turns out that Kimblee roused the antagonistic Russian-like northern neighbors into attacking the fort under the ruse that there were traitors among the Briggs soldiers. There weren't. The result? The attacking force is completely wiped. The Briggs soldiers weren't the blood crest, but ended up making it.
You Are Worth Hell: When he asks her to be his bodyguard/conscience, Riza tells Roy that she'll follow him into Hell itself if that's what it takes. This turns out to be very true — and very mutual.
You Can't Go Home Again: Invoked by Ed and Al. They burned their house down, specifically so that they could not settle back down again. Of course, they do pop by for a visit every now and then.
After Hughes' death, every time Roy has the chance to talk with a villain or a potential bad guy, he coldly asks them whether they killed Hughes, alternatively if they know who did it. When he does get a "yes" out of someone, all hell breaks loose.
In the film Fullmetal Alchemist: The Sacred Star of Milos, Atlas did this to Julia's parents.
Subverted for Julia's brother; he was alive all along.
You Monster!: Early in his duel with Herschel at the climax of The Sacred Star of Milos, Ed invokes this against his opponent.
Ed: How could a monster like you be Julia's brother?!
Zero Approval Gambit: After the telephone booth incident Mustang "kills" Maria Ross. Her partner and parents (presumably) hate him, and the military, Ed, and the reader are convinced that he will do anything to get to the top. Turns out he (very convincingly) faked it.