Arknights: Dreadnought Guards
Leaving aside how well Hypergriff has designed the subclass, they did indeed design the Dreadnoughts with a concept in mind.
Especially Matoimaru and Franka, whose similarities and differences help paint the story of their characters.
Matoimaru and Franka are the only Dreadnought Guards who set their DEF to absolute zero to use their best DPS Skills, and it means the same thing for both of them, but they do it for different reasons.
Matoimaru rates only 'Standard' in Combat Skill and 'Normal' in Tactical Acumen. Her records and voice-lines make it clear over and over again: She's dumb muscle, and in battle she thinks of nothing but cutting her enemies down without considering her own self-preservation or preparing for the enemy's tricks.
Meanwhile, Franka rates 'Excellent' in both Combat Skill and Tactical Acumen... indeed, she is the only Dreadnought Guard whose Tactical Acumen is rated above 'Standard'. Yet she likewise neglects her own defense like Matoimaru, whose Tactical Acumen is ranked the lowest of the entire subclass.
But as I said, the reasons for this reckless aggression are different.
Where Matoimaru forsakes defense because she just cannot bring herself to think of it, Franka forsakes her defense as a deliberate choice. Unlike Matoimaru, Franka is very much thinking ahead and trying to anticipate her opponent's actions to better guide her all-out offense... but she's still taking the same fundamental risk of racing the enemy to see who kills the other first.
And compared to Matoimaru, Franka is less equipped to handle losing that race.
Matoimaru's personal stat balance favors HP over DEF even more than other Dreadnought Guards, and then her Talent takes it further. She has more Max HP than even Skadi, and practically no DEF even before using her S2. Her S2's self-debuff is practically inconsequential. (Narratively, she bases her survival on rapid regenerative healing, matched or exceeded only by the likes of an Abyssal Hunter.)
In comparison, Franka's stat balance is more conventional for the Dreadnought Guards; her HP and DEF are worse than Skadi's, but better than Melantha's. Her DEF is higher than Flamebringer's, but her HP is lower.
But when Franka uses her S2 and sets her DEF to zero, her prioritization of DEF over HP hurts her, because now she has no DEF and she has less HP than anyone in the subclass except Melantha.
Other Dreadnought Guards aren't quite as narratively reckless as these two, of course, so all of the others operate differently.
Melantha is still learning the basics, and remains relatively timid in her inexperience. Though since she's learning under Franka, it will be interesting to see what a Future-Alter Melantha looks like.
Flamebringer only feels alive on the verge of death, but he's apparently much more cautious in battle than Matoimaru or Franka. Perhaps he finds more joy in a back-and-forth exchange of swordplay before he kills his opponent, as his Talent and Skills represent him "coming alive" from fighting and killing.
And Skadi takes some measure of care that no one and nothing makes her bleed, but for the most part rampages through the battlefield like a runaway train. She doesn't forsake her defense simply because she never needs to hit anything as hard as she really could; she puts in the bare minimum effort and still blasts her enemies away.