Almost every character who uses firearms is either someone who sides with the Magistrate or was once part of it. Considering that the Magistrate was the ruling superpower for a long time, they would have the resources to advance their weaponry from swords and arrows to Magitek firearms.
Why is Seris/Abby blindfolded? Possibly because it's common for executed criminals to be blindfolded in their execution. Abby was a sacrifice for the Abyss, a death sentence, so it makes perfect sense for her to wear a fold.
Lian and her bodyguard, Khan, complement each other well. Lian can deal a lot of damage, but doesn't offer much utility outside of damage. Khan has many ways to protect and aid his allies, but doesn't have much offensive power. Put these two together and they cover each other's weaknesses.
Every champion, from Khan, the last character released before the official release of the game, to the next ones after him happen to have foils/are rivals to certain characters that have already existed before them
Furia is a battle hardenedhealer angel who wields the power of the Pyre, with her primary style of play is to heal allies one at a time to increase her attack speed, dealing more damage to enemies in a shorter period, occasionally stunning an enemy directly with a large, incoming beam. Her ultimate allows her to increase the power of her allies. Seris, on the other hand, heals multiple allies at once. Her ability to deal damage to enemies by marking them allows her to damage foes she can't even see anymore. And unlike her sister, she can only stun enemies with a talent, not something she can do all the time. Her ultimate, meanwhile, makes her enemies immobilized for a short time so her allies will tear them down for them. Also, yeah, the whole Abyss thing.
Dredge and Imani are both characters from around the around the same time period. Dredge is simple. He lobs grenades and throws harpoons into the battlefield, uses teleportation to get from one place to another, is a cruel pirate that seeks legendary treasure that's not even his and summons an Abyssal Kraken to help kill his foes. Imani, on the other hand, fires fast ice projectiles and chargeable fireballs at enemies, needs to ride a surfboard made of ice while using her fire as jet engines to propel herself to traverse the battlefield, seemingly wants to do good and ensures that powerful artifacts do not fall into the wrong hands like Dredge's, and summons a dragon from the sky that rains fire onto enemies.
