Psychopath: hehe, stab stab

just some more suggestions.

-i'll be back.
-you do you
-last time i checked you aren't bulletproof
-(mumbling something incohearant)
-yes?
-son you done got a bounty on your head
-im to old for this ♥♥♥♥ (funnier the younger they are)
-all i said was hi?
-i can do this all day
-with every bullet i grow stronger
-cant i just offer you lunch instead?

My suggestions; if they are in severe pain:

-AHHHH!!!!
-NOOOO!!!!
-OWWWW!!!!

shattered empire soldiers: "FOR THE EMPEROR" with the "kill it with fire" precept: "BURN IN HOLY FIRE" also, your mother was a hamster! and your father smelled of elderberries!" "I'd like to see you outrun bullet" if the enemy is hiding behind cover. "I NEED A MEDIC BAG" when injured

"NEVER STOP THE KILLING! NEVER!!"
"STOP DYING AT ME!"
"OPEN YOUR VEINS!"
"You're at least (random number between 100-700) calories."
"How can i snap your neck if you don't have one!?"
"It's a baptism of blood!"
"STOP JUDGING ME!"

most require the psychopath/bloodlust trait, but you probably already knew that.

"Don't touch me!"
"Take this!"
"Ahhhhhhh!"
"That was easy."
"Uh oh."
"Well, I Guess I'm In Charge Now."
"Roger roger"
"It's a trap!"