I think he was in charge of patrolling the borders and babysitting Kaidou and the rest of the brats. He was the most responsibe person in his crew. I don't think he had any specific region inside Wano as he was a warrior, not an opperssor, and his dream was different than Kaidou's.
He likes torturing prisoners
I still believe he does not. He is a killing machine alright, but he was never shown in the manga enjoying inflicting pain like Queen. The only reason people think that is because Queen called him a torture loving pervert. That could also be interpreted the other way around, that Queen was mocking him for being tortured himself back in Punk Hazard. Yes, the anime made him say to Marco that he'd torture him, but the anime had been wrong before, and King was waiting for Joy Boy. Joy Boy is the opposite of a torturer, it doesn't make sense.