The title must be confusing you. Don't worry I'll explain it in a second.
I read a comment on a Batman video about how Batman's enemies represent a feature of himself. I then realized the same could be said to most of the Steven Universe characters. This is at the canon characters, but can also apply to the characters here.
I'm going to be targetted at gems, only two and a half humans are involved with this list. If there's any character that I haven't mentioned that is a gem, you can comment them and I'll try to answer it in the reply. Now, there could be some characters I go more into depth, and some I explain in a sentence.
This is meant to be fun and creative with Batman and Steven Universe. I have played too much Batman Arkham and watched too much Steven Universe.
Steven Universe: The protagonist and the hero of the story. They're willing to do what's right and refuse to take a life. Savior.
Pearl: Elegant and trained with skillful precision combat.
Garnet: Keeps a calm calculated demeanor most of the time and improvise when things don't go according to plan.
Amethyst: Has a unique design that differs from everyone else.
Connie: Above genius intelligence. Although, Batman graduated high school at 14 and went to college while Connie preps for collage at the age 16.
Lapis: Has trust issues with others and is very difficult to earn trust.
Peridot: Reliance on technology (not saying Batman relies on his technology all the time, he relies when it's necessary).
Bismuth: Self inventor. Invents their own arsenal.
Ruby: Has a temper, can let their emotions get carried away.
Sapphire: Using patience along with a clear mindset.
Jasper: Brute force when neccessary.
Greg Universe: Childhood affects adulthood.
Spinel: One very bad experience can change you into someone else.
Yellow Diamond: Strategic and tactical minded when facing against an enemy.
Blue Diamond: Grievance over the loss of loved ones.
Pink Diamond: Dedication to the crusade they created.
White Diamond: Feared reputation and strong will power.
Volleyball: Scars from the past.
Not including small time gems like Eyeball, Aquamarine, Emerald, and off colors because they haven't had enough development for me notice any similarities without reusing the same trait from another character.