Warning: Potential Spoilers!
Corrin: A prince/princess raised in Nohr after being abducted from Hoshido as a child. Can change into a dragon and wield the sacred blade, Yato. He/she is a blatant Gary Stu/Mary Sue and makes terrible life decisions if you choose Conquest. Has the most incestual potential.
Azura: A princess raised in Hoshido after being taken hostage in exchange for Corrin. Becomes unrecognizable while wearing black, even to her close friends and relatives. Her songs sound incredibly stilted and awkward. Most suicidal unit in the army.
Gunter: A Nohrian knight of middling birth who reached his rank on talent and discipline. He now serves as Corrin’s retainer. He is exceedingly eccentric and everyone who knows him calls him weird. Consistently draws attention to his age and the fact that he is old, especially when unrelated to what he is doing at the time.
Felicia: One of the Avatar’s Ice Tribe retainers, along with her sister, Flora. She is a terrible maid and not very good in battle either. The most useless.
Jakob: A multitalented Nohrian butler who serves the Avatar at home and on the battlefield. While generally cool toward Corrin, he's pretty much a total asshole to everyone else, including his son. Not a good person.
Kaze: A Hoshidan ninja. Has an identical twin who looks nothing like him. He is disturbingly loyal to his chosen liege, willing to give up his very life, even if his liege chooses to cut down his friends in front of him. Most likely to betray his homeland for petty reasons.
Silas: A newly appointed Nohrian knight of noble birth. Claims to be a childhood friend of Corrin, who doesn't recognize him. He has a very generic personality. Most forgettable in the army.
Shura: The leader of a group of thieves in Nohr. Former ninja who was forced to become a thief, which is confusing because ninjas are the equivalent to old school thieves in this game and he's actually a totally different class. Great at kidnapping little girls.
Izana: Archduke of Izumo. Descended from a divine dragon, he has amazing hair and a side job as a Loreal fashion model. Often surprises his guests by being a gigantic doofus. Largest ego in the army.
Mozu: A daughter of farmers from a small village in Nohr. Lacks confidence and generally sucks compared to Donnel, who she wishes she was. Has a frighteningly tragic recruitment story for a Fire Emblem Game. Good luck training her in Conquest.
Mikoto: The peace-loving queen who rules over Hoshido. Corrin’s birth mother, but not the mother of the other siblings, which the game expects you to know but doesn't tell you. Puts Corrin's goody two shoes personality to shame. Voted most likely to die early in the story.
Rinkah: Daughter of the Flame Tribe’s chieftain. Passionate and powerful, she's a total brute with zero manners and hates everyone else in the army. Accidentally traded voices with Hinoka in an unknown ritual.
Sakura: The youngest princess of Hoshido. Unlike her Nohr counterpart, she's a likable and reserved character. Also unlike her Nohr counterpart, she is completely outclassed by the other healers in Hoshido. A fair trade. She has a severe speech impediment. The best at giving children a cool hair color.
Hana: A Hoshidan samurai serving as Sakura’s retainer. Her favorite phrase is "get rekt," which Nohrians have come to fear when heard on the battlefield. The best at redefining gender roles.
Subaki: Sakura’s retainer and a Hoshidan sky knight from a long line of talented knights trained to be perfect. His rampant perfectionism annoys friends and foes alike. Is actually a man.
Saizo: A Hoshidan ninja who serves Ryoma and is the fifth to carry the Saizo name. Constitutes one half of the Christmas Ninjas. Curt and taciturn, with his bad attitude rivaling only Jakob. Dislikes everyone more than anyone.
Orochi: A Hoshidan diviner who served the late Mikoto. Her parents gave her a name that means "snake," which is ironically one of the animals that she cannot conjure. Jokes around in times of war, making others uncomfortable. Laughs at inappropriate times.
Hinoka: Eldest princess of Hoshido, she was a noob as a child and let Corrin get stolen by Nohr. After this, she heard a divine message from the Dawn Dragon whispered into her ear: "git gud scrub"
And so git gud she did. Many think she is an alternate universe version of Buttercup from the Powerpuff Girls, but her voice was actually changed with Rinkah's at an unspecified point in the past.
Azama: A Hoshidan monk who serves Hinoka. Likely forced into the shrine by his parents, as his combat oriented growths indicate that his true calling lies elsewhere. Doesn't give a fuck about anything. Trolls harder than anyone in the army.
Setsuna: A Hoshidan archer and retainer to Hinoka. She is known to down an entire bottle of cough syrup before every battle, and her mental state is in question. The biggest weed smoker in the army.
Hayato: An orphan from the Wind Tribe raised by their chief, Fuga. He is a one note character in a game of one note characters, so get ready to hear about his insecurity issues. Not very good at anything.
Oboro: A spear fighter from Hoshido who serves Takumi. Her family ran a tailor shop, so naturally she became an expert spear fighter in the Hoshidan military. Goes clothes shopping in between slaughtering people on the battlefield. The most racist in the army.
Hinata: A Hoshidan samurai from a long line serving the royal family. Shares a name with a useless female ninja from another popular series. His son thinks he's a total dork.
Takumi: A Hoshidan prince who wields the legendary Fujin Yumi. Hates Corrin for no reason. His personality frequently shifts, leading many to speculate that he suffers from bipolar disorder. Most likely to jump to extremes.
Kagero: A ninja from Hoshido and Ryoma’s retainer. Idolizes Bob Ross. She knows she has a nice body and isn't afraid to show it. Voted coolest female in a Fire Emblem game.
Reina: A Hoshidan knight who served the late Mikoto. A closet sadist. Stay as far away as possible.
Kaden: A Hoshidan kitsune who serves as village chief. Manages to get lost so hard that he ends up across the ocean. Promotes into the Nine-tails from Naruto. Has the worst daughter.
Ryoma: The high prince of Hoshido and wielder of the legendary Raijinto. He is such a big lobster enthusiast that he dresses as one in public, much like his late father, Sumeragi. A sweeping whirlwind of death, woe unto those who experience this sea creature aficionado on the battlefield, for he will end you and all of your friends with little effort, all for the glory of Hoshido, with his overpowered range, dodge, offense, supports, weapon, and basically everything else
Scarlet: A hearty resistance fighter from Cheve. Ain't putting up with Nohr's comic book villain nonsense anymore. One of the few people from her homeland with both combat skills and common sense.
Yukimura: Hoshidan strategist and retainer to the late Mikoto. Extremely irresponsible and prone to leaving armies of puppets to defend an entire kingdom. Total nerd. Keeps accidentally breaking his glasses.
Kana: Corrin’s son/daughter, raised in the Deeprealms. Typical annoying little kid. Has her own dragon language that she playfully made up after almost being transformed into a mindless, murderous dragon for the rest of her life. Enjoys being a dragon.
Shigure: Azura’s son, raised in the Deeprealms. The only human being in the world not to inherit their father's physical traits. Shares a love for Bob Ross with Kagero. While mild and kind, he can also be oblivious to obvious things. Didn't realize his voice changed after puberty.
Dwyer: Jakob’s son, raised in the Deeprealms. Lazy bum who possesses talent and doesn't use it, using this combination to justify himself talking smack to his elders and slacking off at every possible opportunity. Voted most likely to drop out of high school and maybe get a GED when his parents get tired of him living at home in his late 20's.
Sophie: Silas’s daughter, raised in the Deeprealms. Her father gifted her with the worst horse imaginable on purpose, which she loves, planting the perfect foundation for an abusive relationship. Eternally optimistic regardless. Her horse, Avel, is legit dangerous and tries to eat people and their hair. A case study for growing up in a bad environment.
Midori: Kaze’s daughter, raised in the Deeprealms. An accomplished apothecary despite being a child, she received her P.h.D. at the age of 13 after witnessing Dwyer's laziness, fearing a bleak future. Her father was creative enough to name her "green," after the color of his hair.
Shiro: Ryoma’s son, raised in the Deeprealms. Doesn't share his father's enthusiasm for lobsters, but loves him regardless. Friendly and skilled, but pales in comparison to his beast of a father. Seriously, nobody can compare to his father. Ever. Forced to eternally live in the shadow of a God.
Kiragi: Takumi’s son, raised in the Deeprealms. A less memorable but more likable version of his father. Like Shiro, his father is superior to him in every way. Just reclass him and give the poor boy an identity.
Asugi: Saizo’s son, raised in the Deeprealms. Totally not Gaius from Awakening. Somehow eats sweets constantly and never gains weight. Really, he's not Gaius, I swear. It's not like his name is an anagram or anything. Voted most hamfisted parallel to a preceding game.
Selkie: Kaden’s daughter, raised in the Deeprealms. No, not the cool Selkie race from Final Fantasy: Crystal Chronicles. Technically half-human, but you could never tell. The most mentally challenged in the army.
Hisame: Hinata’s son, raised in the Deeprealms. A total badass. This guy is basically a nicer Battousai from Rurouni Kenshin with dad problems. Hates his father for being a dork. The coolest child unit and an apology for the decidedly average second generation.
Mitama: Azama’s daughter, raised in the Deeprealms. A starry eyed anime stereotype. Loves to eat toast on her way to school. The most likely to say "uguu~"
Caeldori: Subaki’s daughter, raised in the Deeprealms. Totally not Cordelia from Awakening. Her mother's womb is rumored to contain a trans-dimensional portal.
Rhajat: Hayato’s daughter, raised in the Deeprealms. Totally not Tharja from Awakening. A stalker and occultist, she is creepy AF and everyone is scared of her. Nearly decimates your army before joining and is completely forgiven despite showing homicidal tendencies. A mentally unstable mess.