Vicious has grown up as a physically and emotionally abused child. In session #9, Vicious explains in detail about how his father talked down on him as Vicious shed a tear whilst watching his suicidal mother jump off a building. Their abusive relationship is also visible later that episode when his father beats him (Now as a grown man).
Session #8 - Sad Clown A-Go-Go: A character hospitalized in a scientific institute has gone under medical procedures who forced him to become addicted to Red Eye.
It is said that the first time Santiago took revenge on a man who had wronged him, he ate his testicles. The blood of the man is shown across Santiago's face.
"You'll never know true power until you've tasted the testicles of a man who has wronged you."
Session #9 - Blue Crow Waltz: Spike (then Fearless) kills a girl after telling her to run for her life. The death happens off screen, but you can see and hear Spike firing his gun.
Gren is a male-presenting character played by a nonbinary actor. They are sometimes wearing dresses or corsettes.
Their gender is never explicitly identified in the show, they are only addressed by their name. I don't remember any instance where they are misgendered.
There is a nonbinary actor who portrays a male-presenting character -Gren- who wears both suits and dresses through the series. Their gender is never explicitly identified in the show. No jokes, They are just accepted.