Normally, the series has the characters' bust shots talking to each other, but in Fire Emblem 7, this actually makes the most sense. Most of the time... it's actually as if you're viewing it from a character who's standing right there... and you are. You're viewing it from the Tactician's point of view. This explains why they sometimes look towards the screen and address you.
Also, Marcus. In Fire Emblem 7, he's actually not a bad fighter and is a Crutch Character who fits the Oifey stereotype better (a pre-promoted unit who actually maintains usefulness throughout the game.) In Fire Emblem 6, he's practically Jagen incarnate. Fridge Brilliance? In Sword of Seals, he's much older. In 7 he's as much in his 40's, which would make him at least 60 in 6... and considering the stress of being a high-ranked member of the military, he may be even older than the average male in these days.
Similarly, people complain about Renault's extremely low stats for a supposedly high-ranked Bishop... but these make sense once you remember his backstory. He used to be a mercenary, an expert in sword fighting, who went into the clergy decades ago to cleanse himself from the horrible sins he had committed in his past; switching pretty much everything in his fighting style/gameplay must have taken a HUGE toll.
Further Fridge Brilliance: If Renault was still a physical unit instead of a Bishop, he'd probably have a really high strength stat. It certainly explains why he has a pretty decent defense stat for a magic-user.
Even further, in the Reclassing system introduced in later games, going from a physical class to a magic class typically results in very low magic stats, and most characters who start off as physical classes make terrible magic users. This is probably exactly what happened with Renault.
In Fire Emblem 7, Serra has notoriously slow-building supports. The reason? Because many of the characters, including those she can support with - Erk being the prime example - canonically find her annoying, so it takes them a lot longer to warm to her, only seeing her Hidden Depths when they're able to go past the "annoying little girl" facade.
Same goes for Vaida and Renault. Vaida is extremely difficult to approach and hold a conversation with, even if you're not afraid of her, and Renault is an angst-filled atoner who prefers to keep to himself. Heath and Legault are similar to Renault in this regard. There is also the point that they are former enemies to most of the other characters. They are only saved from isolation because that trait also makes people curious as to why they left their organizations, which comes up in most of their support conversations. Also, Lucius has many slow moving supports because he's very withdrawn due to his horrible past. Also, Matthew, Oswin, Raven, and Sain all have relatively low support gains. Matthew is attracted to shady people like him who are usually the quiet types. Oswin IS a quiet type who is also very critical of others. Raven has good support growths with the only two people he trusts, otherwise he is annoyed greatly by his other supports. Finally, Sain is a perv and most of his supports are women. His personality makes it hard for women to take him seriously.
Similarly, the following characters only have three support options each: Ninian, Rath, Merlinus, Hawkeye and Jaffar. Each one has good reasons for it:
Ninian is quiet and asocial, feeling uncomfortable around the army due to her being different from them. She approaches Eliwood to thank him for saving her a year ago, Florina due to their common shyness, and Hawkeye approaches her.
Rath is Not Good with People due to spending most of his life alone. His fellow plainsfolk (Lyn and Guy) are the only ones he'd feel comfortable talking with, and Wil hangs onto him like the social, friendly fellow he is (leading to a Heartwarming Moment in their A support). In addition, Guy comes from Rath's tribe, and was curious to meet the son of the Kutolah leader since Rath left the group when Guy himself was a toddler.
Furthermore, it probably helps a lot that Rath had already met Lyn and Wil before, making it a heck of a lot easier for him to feel comfortable around them.
Hawkeye is a serious guardian who would rather focus on duty than socialize, so of course he'd only take time to chat with his friends Pent and Louise. As for Ninian, he already knows of her mixed heritage and their conversations are all about Arcadia, a hidden paradise where dragons live alongside people.
Jaffar is a confirmed murderer and Not Good with People either, as he only very recently has started to develop anything similar to human-like emotions. So naturally only his best friend/prospect love interest (and the person whom he's redirected his loyalties to), former fellow Black Fang members who know him from the start, and the lover of the woman he killed before he pulled his Heel-Face Turn (which forces him to see the consequences of his Kick the Dog moment) would be especially interested in talking to him.
Who wants to stand around and chat with the transport? Marcus, serious and dutiful. Nino, cheery and curious. His third option is Vaida, whom he's absolutely terrified of.
Many people have noted how Sain and Lyn have no supports, which seems to clash with his claim that he has a crush on her. You see, Sain makes his claim when he's talking to Kent about *Kent's* crush on her. (Which can be taken to the next level if they have an A Support). In-story, Sain actually has no supports with Lyn because, being both a Knight and the closest friend of someone whose Bodyguard Crush on Lyn he's aware of, he doesn't want to be alone with Lyndis.He's afraid that, if this did take place, he'd give her a Love Confession and completely bypass Kent's feelings in the process; a Love Triangle like that in the middle of war would be extremely uncomfortable, and with good reasons.
Also, there is the lack of an Assassin class in Binding Blade. It can be explained in-story with relative ease: the only way to promote a Thief into an Assassin is with a Fallen Contract, which you get when you defeat Sonia. (Heck, you can't even use an Earth Seal on them.) The only ones who have said Contracts? The Black Fang, aka the same group you must destroy to save the world.
The Dragon True Final Boss of Blazing Sword won't move, unlike the other two True Final Bosses of the Fire Emblem GBA games. Why is that? Because he has to stay near the Dragon's gate to stay in Dragon form. If he moved away from it, he'd be subject to the laws of reality that the ending winter set in place; he'd have to change to humanoid form between attacks, which is what doomed the dragons during The Scouring. Since the Fire Dragon is designated as a survivor of that war, he'd know better than to weaken himself that way.
That also explains why Ninian was able to revert to her original Dragon form without using a Dragonstone. The whole "Nergal verbally pressures Ninian and makes her go Dragon" incident happened when she again refused to open the Gate for him; as Nergal gave her the Breaking Lecture, Ninian (who already was a bit emotionally unstable, judging by her talk wit Nils in Bern and, if obtained, her Eliwood supports) snapped and let the Gate's power flow through her, which made her shapeshift into a Dragon. How did she last so long in her Dragon form until she was slain is more questionable, but it could be inferred that Dragon!Ninian saved up her energy via flying as fast as she could to find Eliwood instead of attacking anyone in her path. (Not to mention, by looking at the map, it seems that the Dread Isle isn't that super far from the Ostian cavern where Durandal was sealed; by flying at top speed, she could have covered such a distance with relative ease in few hours.)
Of the three anima mage units, Erk is the one most susceptible to RNG screwage, especially where his magic growth is concerned. But when you read his supports with Nino and Pent, you find out that he not only has a tendency to overwork himself to exhaustion but that it took him longer than his mentor or Nino to learn to commune with the spirits, as is crucial for anima masters. Plus, there's his inferiority complex in general. This coupled with his over-focusing on the technical and intellectual aspects of magic mean his growth is going to be a bit slower than a seasoned master and a prodigy.
Most Western gamers have played Blazing Sword before Sword of Seals, blissfully working for the A-level supports with Eliwood and Hector for their preferred ship. Now download the previous game and—hey, guess what? You doomed that woman (whichever lady you choose) to dying soon afterwards! Hope you enjoyed that moment of Squee, you bastard/bitch.
Well, if you pair Eliwood with Ninian, it's stated she's not going to live very long anyway. Whether or not that actually makes it better is debatable, though, and Hector's poor wife is still out of luck either way.
Similarly, Eliwood and Hector's supports take on a very different tone if you've played Sword of Seals first. (As was the intention, since Blazing Sword is a prequel) Their B Support is direct Foreshadowing, but their A Support, with them promising eachother they'll stay alive, and Hector's line "Well, then letís live long and in health! I donít want to hear any excuses about not being able to come help when weíre old men" is tragic Dramatic Irony as Hector dies very early in Sword of Seals' storyline, and Eliwood wasn't able to come and help him.
Considering Kent's Bodyguard Crush on Lyndis (which is referred to by Sain in their supports) and Florina's Romantic Two-Girl Friendshipwith her, this could be also applied to them if you have her romanced by Eliwood, Hector, or Rath. Unless you have them paired off with others, which is relatively easy in the case of Kent since he has potential endings with Fiora and Farina... but Florina only has endings with Hector and Lyn, so if both Hector and Lyn are with others... Poor Florina.
But, you ask, "Why on Earth would attacking Fargus cause a Non-Standard Game Over?" Well, if you don't get a boat, you can't get to the Dread Isle. If you can't get to the Dread Isle, Nergal's men would in all likelihood easily capture Nils and Ninian. If Nergal has Nils and Ninian, he can open the Dragon's Gate. If the Dragon's Gate is opened, Dragons will come out. If Dragons come out, then, to quote Athos, "The continent will be ash in less than a month." So, by being Too Dumb to Live and attacking the only guy with a boat and who's willing to use it to take you towards the Dread Isle, well, Sonny Jim, you've just caused the apocalypse. Have a nice day.
Imagine what would have happened if Nils hadn't been so lucky as to run into Lyn during her quest. He and Ninian would have been easily taken back to Nergal, he would have summoned the dragons a year earlier with no one around to stop him, and the world is destroyed. Not helping matters is, even if Lyn succeeded in her journey anyway, she would have gotten very little time with Hausen.
Although it is also hilarious, Sue could be Rath's and Lyndis' daughter. Roy could be Eliwood's and Lyndis' son. Roy and Sue can be an item, which implies that it's possible that the relationship is incestuous, despite Sue and Roy both being the children of Lyn being pretty much impossible... unless she cheated...
Lyn is also potentially Lilina's mother, meaning that would have to be some pretty serious cheating for any of Roy's love interests to be his half-sister. Much more plausible, however, is him and Lilina potentially being cousins (by way of Eliwood/Fiora and either Hector/Farina or Hector/Florina).
Hey, remember when the dragons come? Well, Ninian is forced to kill them. After the battle, she says a Blink And You Miss It line by saying the dragons were "children". That could mean that they are young by their race's standards, even if that means they are a few centuries old, they still would have the minds of children. Oh, and by the way, if those incredibly powerful dragons are children and the last dragon was already wounded by Ninian, then how un-godly powerful is an adult, healthy dragon like?
Considering that Ninian at least looks equivalent to mid-to-late teens/maybe early 20's, and she managed to kill two and wound the third, that ought to give you a pretty good idea. Also, it makes you pretty glad that Ninian is otherwise gentle by nature, huh?
On a related note, these implications about the power of a true dragon make it much harder to believe that Jahn was a full strength dragon. Either he had regained much less of his power than he seems to believe in his battle quote, or...
In his epilogue, Karel eventually becomes known as the Saint of Swords. Guy also becomes known as the Saint of Swords, which is most likely a mistranslation on Guy's part since his character title still says that he's the Mounted Swordsman, and many consider Karel to be the true Saint of Swords.
To be more specific, during their support conversation, Karel and Guy agree to have a match a year later after Guy becomes as strong as he can. Given both Karel's nature and Guy's resolve, this most likely will be a death match. Since Karel appears as an old man in Sword of Seals, it can be assumed that he won the match and killed Guy for good.
Rebecca can be in a relationship with Wil, Sain, or Lowen. Rebecca, Wil, and Sain all have brown hair. Rebecca's son, Wolt, has green hair like Lowen. However, the father doesn't have to be Lowen due to the creators wanting to keep all possibilities open. How is it that Wolt can have green hair if the father is Wil or Sain?
Rebecca's hair is green. Granted, Wolt's hair color is closer to Lowen's than Rebecca's, but Wolt getting green hair because of Rebecca isn't totally impossible. (We never see her Missing Mom, so for all that we know Wolt got his hair from his dead grandmother.)
Also, Wolt can be seen as a physical mixture of all of his potential dads. He has Wil's hairstyle and fighting class (the latter shared with Rebecca), Lowen's hair color and personality, and Sain's eyes and features. (And he is specifically mentioned to not really be a lot like Sain anyway.)
Traits like hair color can skip generations. It is entirely possible that either Wil or Sain (or even Rebecca herself) inherited the gene for Lowen-green hair from an offscreen green-haired ancestor, but don't display the trait themselves. Their offspring would be able to inherit that gene, and by extension display the trait, which would result in a kid with green hair. No Fridge Logic here.
I just realized something, though. After playing the game and promoting Rebecca, her hair became a lighter shade of green. Maybe it was her head-band that made it look brown, though still looks dark green in the artwork. Mheh.