The Night Blade and the Sougetsu Family (Yuzuriha's clan) have been around since ancient times, with many of their members undergoing rigorous training passed down from generations. As such, characters affiliated with them tend to demand good execution (inputs) and fighting game fundamentals.
Linne would make an amazing high-mobility Shoto Clone if not for her weak normals that causes her to deal only small amount of damage, which is made up for with a multitude of multiple-hitting specials. Being immortal does wonders for learning how to fight, but not so much when you have to live as a little girl. Her experience is instead translates into her cross-up dodge roll and various optional follow-ups that let the player baits wrong reaction out of their opponent and breaks their defense with some educated guess.
She generally does terrible at anti-air because she is short.
Seth is a notoriously difficult character to use due to his Extremity Extremist close-range toolkit. Seth is not a fighter, he is an assassin. Because of his low health, Seth needs to constantly have the initiative and prevent opponents from having breathing room since he cannot win in a direct battle of attrition. Seth's playstyle also draws parallel with his childhood life: a fighting-game newbie will need to spend a lot of time practicing their input execution a lot just to achieve any sort of competency with him.
Yuzuriha's Flash Step and the ability to get at her foe from nearly any position not only reflect her carefree nature, but also how she is the guardian of her land. "This is my home. I will fight wherever I want!"
Word of God has stated that Waldstein taught Linne how to fight, and Linne in turn taught Hyde how to fight. You can see a lot of similarities in their respective fighting styles, most prominently, they all have a Deadly Lunge attack that involves swinging a bladed weapon at a downward angle, with it getting more and more dynamic with every generation (Waldstein's Eisen Nagel > Linne's Flying Swallow > Hyde's Bend Sinister).
Another thing of note is that all three of these attacks are part a series in their respective character's movelists. Waldstein's Eisen Nagel has a follow-up attack that allows him to get some extra damage in, fitting his brutish, warrior nature. Linne's Flying Swallow doesn't have a follow up of any sort, but she is able to IC the attack to hit low and cross-up her opponent, which plays into her gameplan of trying to look for an opening in her opponent's defenses. Hyde's Bend Sinister is a follow-up to his Black Orbiter, and is often used as a combo-ender, which makes sense considering how Hyde tries to get things done as quickly as possible.
All of the playable Licht Kreis members lend themselves towards some sort of offense and often suffocating strategy, with them being 'invaders' that come into Kanzakai seeking to regulate EXS use. Even oddities like Waldstein, who betrayed the organization has his long arms to threaten people with, and Londrekia from brother organization Ritter Schild has Circular Step along with the threat of freezing debuff to keep the opponent on the defensive for extended periods of time.
Amnesia members and independent human characters such as Phonon or Carmine are often more creative and flashy with how they manifest their EXS, being amateurs with no strict rules. Compare them to Night Blade's enhancing of bodily ability, or Licht Kreis' outward and direct EXS application.
Amnesia are essentially young delinquents that are hopped up on EXS. Hilda, Gordeau and Chaos all rely on great wide-area special attacks manifested by EXS to compensate for their relatively poor normal attacks. The only person this doesn't really apply is Enkidu, the oldest of the four, who cannot use his EXS to his fullest extent without exerting himself, which is integrated via his short-reaching but devastating normals, and his largest attack, as well as his only projectile, being a super move that requires either full meter to use, or being in Veil-Off.
Gordeau's play-style revolves around threatening the opponent with his large scythe attacks and command grab mix-up. You could say that this Grim Reaper is scaring people from pressing buttons against him. His Reaper motif may or may not have something to do with the death of his friend Roger as well.
Phonon and Hilda both covet their EXS abilities. But while Phonon enjoys playing with her EXS power (as reflected in how her moves pushes/pulls her opponent where she wants), Hilda tends to be more irresponsible with it, either lazily pummeling opponents from a far over and over, or set up her delayed special attacks in a manner that makes the opponent 'dies on their own sword' instead.
Merkava and Vatista, two Void-related entities, use unorthodox inputs or strategy to highlight their otherworldly-ness.
Merkava's play-style represent two halves of his personalities. There are his long-range moves that's not so much for rushing down the opponent but trying to keep them away. The ones that don't are his repressed Void side grabbing and eating those people. His flight ability can be used to either avoid or making a pass at the opponent, much like birds fleeing from danger or swoop in on a prey, reinforcing his nature.
We are told in the story that Vatista has a Restraining Bolt command built in to prevent her from using her full power against humans. Those weird forward charge motion and negative edge inputs, even for a simple space-control move, seem like she's trying to work around the rules.
Vatista's FLS Ability, Restriction, allows her to cut off the flow of EXS in her surroundings, prohibiting an In-Birth from using their full power against her. In actual gameplay, this is integrated by her not being able to be counterhit whatsoever.
Unless you're Enkidu. Because of him not being able to use EXS to the extent as the rest of the cast, as well as his Havoc mechanic, he is technically the only character who can counterhit Vatista.
Imagine a beginner Carmine player blending people left and right with his strong space-eating moves and pressure, only for an experienced opponent who knows the matchup tricking Carmine into pointlessly wasting a lot of blood and bodying him, prompting the player to learn how to fight correctly. This is basically Carmine's entire mindset when it comes to fighting.
Hyde has the most straight-forward fighting style in the cast, which reflects on his character really well. Hyde is a Shotoclone whose specials cover any situation, showing that Hyde at the very least learned the fundamentals of fighting with his EXS in order to defend himself against anyone that attacks him. To make full use of his abilities, Hyde players must play him as aggressively as possible using his Vorpal Trait to inflict Scratch Damage to defending players reflects Hyde's brash and honest personality, as well as his lack of control over his unstable powers, since Hyde comments that sometimes his sword moves his body. The fact that most of Hyde's normals inflict damage on block means that he can run the timer out while whaling on a defending enemy, signifying that while Hyde is willing to fight and defeat others in order to achieve his goals, he doesn't have to if he can help it which is appropriate for a Nice Guy. Finally, his lack of standing overhead and start-up delay means that unlike Linne and more experienced In-Births, Hyde's mix-up game is sorely lacking, which not only points to his inexperience in using his powers, but his inability to lie as well.
Hyde makes an off-hand observation in Nanase's Chronicle Story, saying that he could easily take down a girl with a low kick. Two of his non-Insulator based attacks are a low-kick and a sweep respectively, which he uses to add pressure to an opponent and knocking them down so that he can further punish them. Not to mention that half of the roster is female, which goes full-circle with his comment.
All of Hyde's Insulator-centric normals deal chip damage, which is something that's generally attributed to EXS specials. The Insulator itself is said to emit destructive amounts of EXS with each swing, not to mention that Hyde constantly fights with the sword in hand, rather than manifesting it whenever it's most convenient for him, like Gordeau.
Byakuya's entire Animal Motif is that of a spider, with his eight Predator blades and his webs, but these motifs also factor into his fighting style. If it wasn't clear enough already, Byakuya is a cold and sadistic psychopath underneath his unnervingly cheery and polite exterior, and he takes pleasure in playing with his victims, much like how a spider plays with its prey. His Predator-based attacks are used to inflict as much pain as possible, with him repeatedly cutting away at his opponent or skewering them from every possible angle, once again hearkening back to how cruel spiders can be towards their prey. Another thing to note is how spiders can taste and smell using their legs. Byakuya is also a cannibal, meaning that not only is he tormenting his opponent with his blades, he's also getting a taste of them while he's doing so.
Spiders are commonly portrayed as habitual creature who do most of the living in their web. And the game uses this to represent Byakuya's unwillingness to get out of his old life (moving past his sister's death) and how he get other people tangled up in his personal problem (in this case, Strix)
Nanase is a pure rushdown fighter like Hyde, her target. Unlike Hyde's more straightforward approach, Nanase focuses more on utilizing Confusion Fu in order to trip her opponents, much like her innocent use of Insane Troll Logic which created enough misunderstandings among Hyde's friends to mistake him for a sexual predator.
Akatsuki is Fish Outof Water both inside and outside of story, being a man out of time (out of franchise even) and carried his basic Shotoclone moveset over to a game full of zoning monsters, forcing player to rethink how to utilize him.
Eltnum, whose Arcade storyline is a Shout-Out to French Bread's earlier cult classic Melty Blood, is a rushdown character with higher skill demand than what is considered normal for the archetype (having to play around opponent's Shielding and defense habit, which is something not easily picked up by new FG player) As if French Bread expects those who pick her up to have played Melty Blood to death or have good grasp of fighting games already.
