These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternative Character Interpretation: This is canon for Marth. He's always been noble and brave to a degree but in the earlier games he was decidedly naive and a bit of a bleeding-heart, apparently so much that the OAV adaptation removed the brave and noble part and upped the softness. In Super Smash Bros. Melee, he was something of a show-off. Finally, Shadow Dragon introduced a bolder, more serious version of the character.
It even gets lampsheded in Fire Emblem Awakening: Lucina believed Marth to be The Stoic and used said interpretation as a base for her "Marth" disguise. Tiki corrects her in their supports and states that Marth was a kind and gentle Magnetic Hero.
Adaptation Displacement: Outside of Japan, Marth's much more well known for appearing in Super Smash Bros. than his own games; the release of Shadow Dragon didn't actually do all too much to dispel it, as it was a fairly quiet release.
Big Lipped Alligator Moment: The Pyrathi chapter. Not because of anything that happens in it, which is all in the bounds of the game itself - but because Pyrathi is never even so much as mentioned again afterward, in any of the games. As soon as you clear the chapter, the ending cutscene doesn't mention anything that just happened, instead segueing directly into Catria arriving to deliver a message from Minerva. The SNES remake even cuts that chapter out entirely.
Word of God says it's Ogma's hometown. Strangely this detail is never even brought up in the games proper.
CanonPurity Sue: Arguably My Unit - who really doesn't have any kind of personality beyond being unfailingly loyal to Marth but somehow gets heaps of praise and adoration mounted on them. Though the game tries to paint them as a pragmatic alternative to Marth in certain scenes, particularly just before the final chapter, the fact that they are every bit as pure as he is means that it doesn't really take. The fact that they're also a blatant Audience Surrogate doesn't help either.
Demonic Spiders: Wyverns (or Flying Dragons) in Mystery and its remake, but especially in Lunatic Mode of the latter. All dragons are pretty bad, having defence-ignoring breath, but Wyverns stand out due to their massive movement range and flight. They have a very annoying tendancy to circumvent your meatshields and pick off vulnerable characters in the rear, not helped by the first time you face them being a desert chapter where your movement is already heavily restricted.
Elice is loathed by Merric/Linde fans; ditto for Est, in regards to Palla/Abel. In the case of the latter, Est actually marries Abel, but they're separated during Mystery, which opens a whole new can of worms.
Ensemble Darkhorse: The Archanea canon as a whole is easily the most popular and famous in Japan, in contrast to the rest of the world's view of them; Mystery of the Emblem, in particular, is beloved and heralded as the best.
Ogma is considered a great unit overall and started an archetype that fits this trope.
Like Ogma, Navarre started an archetype and is said to have inspired the Myrmidon class he would later be reclassed as in the remakes.
After Shadow Dragon, Wolf's good growths, Bishōnen looks, and sympathetic background made him very popular.
Catria is one of the more popular characters from the Archanea games.
Legion. Well, sort of. Among the FE Game Mod community, he's a very popular character to insert into hacks.
A particularly odd instance: Vyland, among the Japanese fandom. Despite his dubious usefulness and utter genericness in a game with both far more developed characters and a billion better Cavaliers, he has a bizarre borderline-memetic following in the Japanese fandom.
Ditto for Wrys, seemingly due to his baldness. To the point where he can convince your MU to shave their head in New Mystery. It appears his recruitment quote ("I can't fight, but I can heal others with my staff") have reached borderline memetic status among the Japanese fandom, given how he repeats it word-for-word in New Mystery.
Some fans think Catria's a better match for Marth than Caeda. Miraculously, they're more often than not pretty civil to Caeda herself.
FanonDiscontinuity: People seem to be treating Michalis's optional survival in New Mystery as this. His ending isn't helping matters either.
Game Breaker: The original, and perhaps one of the most overpowered Lord in Fire Emblem series, is none other than Dark Dragon Marth. Marth has stats that, while they may seem unimpressive at first, happen to be enough to singlehandedly trivialize the early chapters and enough to last him throughout the entire game with little to no support. Marth has dominance over several broken resources, including the game's ridiculous version of stats boosters. However, on top of this, Marth has an exclusive acess to three exclusive weapons: the Rapier, which is buyable for most of the game for 900 a piece, and is effective against Armor Knights and Cavaliers which make up 80% of the enemies in the game; Miracle Sword, which is acquired mid game and is one of the strongest weapons in the game (and boosts his growth rates to boot); and the Falchion, which allows Marth to ignore direct attacks and allows him to defeat Medeus. The only time Marth can have any sort of difficulty is during the small part of the early game where he is stuck with his decent, but not impressive stats against Axe Wielder bosses, and against Camus.
The so-called Christmas Knights (Cain and Abel duo). Both units join in the first chapter, have both of the best weapon classes available, have great bases, and arguably some of the very best growths in the game. It's no wonder they have always been top tier in the FE1 remakes. Mystery of the Emblem instead gave us Luke and Rody, who have rougly equal bases to what Cain and Abel had... but with even better growths, having some of the best growths in the series. The Paladin Class has always been on the edge of gamebeaking in FE, and these guys are part of the reason.
Alongside Cain and Abel, Hardin in the original is Jagen thanks to his ability to wield the Silver Lance with an actual growth rate who joined at chapter 6. In both the original and book 1 of Mystery, Hardin is usually considered the best Cavalier in the game.
Dark Dragon in general, being a relatively outdated game, has tons of this. One of the more notable examples was the ridiculous stats increasing items, which give boosts of around +4 or +5 compared to the +2 of later games, while the stat cap in this game is 20. Safe to say, most of them are nerfed considerably in the more modern games, and for good reason.
Catria, and to a slightly (but only very slightly) lesser or bigger extent Palla, in Mystery and its remake. Catria joins in chapter 2, with decent bases, amazing growths and excellent mobility (being a flyer and all), alongside the ability to use Silver Lance right off the bat in Mystery. Palla joined one chapter later with even better bases and the ability to use Silver Lances right off the bat. Sure, she has a bad Speed growth, but her speed base is so high it really doesn't matter, even worse in Mystery where she has 16 speed in a game where 20 is the speed cap. Is it any wonder that most Lunatic playthroughs rely on them both extensively?
Caeda in the remake. Caeda has an exclusive access to the Wing Spear, a Rapier expy, except stronger (8 MT, which translates into 9 extra damage compared to the Rapier and did not face Weapon Triangle disadvantage). This weapon allows Caeda to curb stomp any Horse riding and armored units, both of which filled the map in Shadow Dragon. To top it off, Caeda has an extremely overkill speed growth, and the forge mechanic allows her to mitigate her low STR, especially notable with forged effective weaponry, which gets +3 Damage for every MT forged on it, such as the aforementioned Wing Spear, and her flying traits gives her absurd versatility in term of applying her offense. Promotion into Dracoknight also makes up for her weak points (low STR, HP, and DEF). It says something when Caeda barely gets buffed in the transition to New Mystery, her Wing Spear gets significantly nerfed because New Mystery is not as much of a Cavalier + Knight Swarm as Shadow Dragon, and she is still up there with Palla and Catria (both of which enjoyed a massive amount of buffs) for the best character in the game after My Unit.
The Warp Staff in Shadow Dragon. It allows you to teleport one of your units anywhere on the map, even right next to the boss. Oh, and it has 7 uses (unlike previous games where it usually had 3), you get it really early and, you can find more. By abusing it, you can complete most chapters in the game in 2 turns or less. It's nerfed in New Mystery simply by virtue of coming much later.
Ho Yay: Rickard has a pretty blatant crush on Julian; he even ends his dialogue with hearts when talking to him.
Narm: In Mystery of the Emblem, Lorenz bites it in the first chapter. How is this represented? His sprite explodes. Clouds of fire, sound effects, the works. This was changed in the remake.
This piece of artwork◊ for Shadow Dragon would be all well and good... except everyone's expressions (especially Ogma's) are really Off Model, undermining any attempt to seriously appreciate it. Thanks for that, Shirow Masamune.
Older Than They Think: Some fans who started with one of the non-Japan only games might be surprised that the series goes as far back as 1990. It's also quite surprising how many features that are considered a series staple were already in the first game.
As of Awakening, the Avatar creation system has also fallen into this, to the point where many western reviews (and Nintendo of America themselves!) claim Awakening invented the system.
Rescued from the Scrappy Heap: Katarina was originally dismissed as random fan-service when first announced, but when she reveals herself as an assassin it's actually quite unexpected.
While originally seen as a benchwarmer prepromote, Wolf's improved growths in Shadow Dragon made him really popular.
Like Wolf, Sedgar got a massive popularity boost after Shadow Dragon improved his growths. Some western fans worshiped him for a time, even comparing him to The Juggernaut.
Jagen has technically been saved from the scrappy heap a long time ago, since most fans of the series who know their stuff are aware that he's actually pretty great for the beginning, much like several later characters of his archetype.
Scrappy Mechanic: In Shadow Dragon, having to kill off people to get the sidequest chapters. Also the reclass system, to some.
Seinfeld Is Unfunny: Most of the criticisms towards Shadow Dragon can be attributed to this, being that it left the 18-year-old core Dark Dragon game alone and made only a few tweaks beyond the obvious presentation facelift.
The original games themselves really suffer from this. NES Shadow Dragon started a genre, true, but as a result of being the first (and the game being on the NES) the interface practically qualifies as a war crime, animations are molasses-slow, especially on the map (and are unskippable) the plot barely exists, the graphics are ugly even for an NES game, and once a few certain characters promote difficulty goes out the window. Mystery of the Emblem on the SNES is somewhat better (see below), but it still lacks attack ranges on the map, the animations are still slow (armored knights, jesus) and while the plot is better, it still lacks some of the elements (like supports) that most modern fans would think of as defining Fire Emblem.
With the release of Fire Emblem Awakening, New Mystery as a whole has fallen into this. Generally considered a Surprisingly Improved Sequel and a great addition to the series at the time it came out, with its No Export for You status combined with Awakening taking everything good about it Up to Eleven, the game will most likely be doomed to obscurity among many western fans, though with the fan translation for the game, it's known to die hard fans.
So Okay, It's Average: This seems to be the general consensus on the remake, Shadow Dragon. If you get past the flaws, the game's just...average, even for a Fire Emblem game.
Surprisingly Improved Sequel: Mystery of the Emblem to the original Dark Dragon. While the latter was a good game that helped establish a genre, it was plagued with a terrible inventory system, staves didn't give EXP, the graphics were rather bland, and the story barely existed. Then the former comes and fixes most of the gameplay flaws as well as adds much-needed character and story development, and wraps it up with a more streamlined version of NES Shadow Dragon.
Many fans consider New Mystery to be this to (DS) Shadow Dragon too. It takes the Adaptation Expansion route rather than being a straight remake, adds a support system for much needed character development, and you no longer need to kill off your own characters to get the sidequests.
That One Boss: Dark Dragon for the most part is a really easy game. That being said, Camus is a good example of this trope in the first game. Camus has a solid stats and wields the lance Gradivus, which gives him high attack power and a 1-2 range. Camus is arguably the only boss that can't be trivialized by the Game Breaker Marth. Hardin in the third game is one as well; coincidentally, both of them wield the Gradivus.
Tier-Induced Scrappy: Only six classes could promote in FE1, automatically writing off most units who could not. FE3 slightly improves this by connecting four existing classes into lines, and the DS remakes feature lines introduced later, even going so far as changing certain mercenaries into myrmidons! The DS remakes improved things by giving non-promotable classes an actual promotion or higher caps to make up for it, such as giving Marth a 30 level cap to work with.
Jagen is probably the most affected by this. In the game's universe, he's considered a Cool Old Guy, veteran knight, and tactician. In real life, he started an archetype of EXP THIEVES!
Then came the Metagame shift, and people cared more about availability than growths, causing all Crutch Characters to become more popular.
Wrys is surpassed by Lena in both growths and base stats, so he is not considered very useful despite appearing in the very first chapter.
Unlike the rest of the members of the Wolfguard, Vyland's never been good.
In both games and the remakes, Bantu starts out with pathetic stats and has possibly the worst growths in the game.
Boah is hated for having the worst growths in the game and being the weakest of the potential mages.
Rickard is usually considered inferior to Julian in terms of growths.
Every character who joined after the Sable Knights in New Mystery, thanks to the combination of low availability and terrible base stats for their join time. There's a reason that Character Tiers for the game usually ignored them and considered them as Free Items instead of a new character.
Viewer Gender Confusion: Marth was a pretty common subject of this among western Super Smash Bros. fans, as his design in those games seems to lend itself to making that mistake. In everything other than SSB, though, it's hard to make such a mistake.
Rickard due to his long hair, big eyes, and apparent crush on Julian.
Many have mistook Xane for a girl.
Vindicated by History: Jagen and the Jagen Archetype. They used to be hated by the fanbase, and then the metagame shift happened and Jagen has a much better position. Ironically, some the players even discovered that Oifaye actually is worse than the original Jagen.
When Shadow Dragon comes out, Caeda is considered a High Tier mage, but nowhere near the Top of the tier list, which is populated by Wolf and Sedgar. And then people discovered how to really use Caeda. Nowadays, Caeda is considered the best character in the game alongside Lena.
What Measure Is a Non-Badass?: Nyna gets this from some fans. Considering how tough her life has been, it isn't surpising she suffers from emotional damage! Considering her shattered spirit, is it really surprising she handed her kingdom to Marth, after all the mess she was a part of?! Some fans also tend to blame only her for all that happened in book 2, forgetting over Boah and Hardin's in it(In Universe, all three characters blame themselves).
Caeda is sometimes called a slut for daring to use her good looks and charm to recruit guys into the group. Many of the people who never played Fire Emblem Archanea, or only watched the anime, also excuse her of being a Faux Action Girl. This is despite Caeda never getting kidnapped, and being a Lady of WarIn-Universe as well.
Far more likely 1 as people were expecting more than a "prettied up" port with questionable graphic style (the majority of the fanbase being far too used to games with better/flashier graphics), and overlooking that overly remaking the game would partially defeat the purpose of it: To show the series' roots.
The Woobie: Wolf started out his life in slavery, is forced to choose between his hero/best friend and the right thing, and he never gets over Hardin's death.
Princess Nyna, too. Nothing ever goes right in this lady's life, and the mistakes she commits while trying to fix things make it worse.