Changes

Often just called "Cartman," he is arguably the main character of the show. He is obese, bigoted, narcissistic, and generally sociopathic; he was originally conceived as an eight-year-old version of Archie Bunker from [[All in the Family]]. He is very antagonistic towards Kyle, largely because of Kyle's ethnicity. (Cartman is anti-Semitic and admires [[Adolph Hitler]].) Fights between the two, usually stemming from mocking each character's respective obesity and ethnicity, have become a centerpiece of the show. Ironically, however, each has saved the other's life twice. All three of the other boys are open about their dislike for Cartman, but they still usually refer to him as their friend. Cartman has been shown to be extremely intelligent and manipulative, and he has a dark charisma that makes him a natural leader of the boys in times of adventure. Cartman's sociopathy has been traced to his upbringing by a single mother, Lianne. Lianne encourages Eric's obesity, and treats him like a friend instead of a son, thus not disciplining him. Lianne, a "crack whore" in the show, was also the name of Trey's former fiancee who Trey saw cheating with another man.

Though not originally a main character, Butters has seen considerable airtime since season 5 and is often considered the "breakout character" of the show. He is kind, wholesome, and trusting to a fault - in other words, he is basically the opposite of Cartman, and many episodes have been devoted to the relationship between the two. His parents are [[mentally ill]], with his father showing obsessive-compulsive behavior and mother having issues with anxiety and panic. Butters' mother attempted to kill him in one episode. During season 6 when Kenny was absent, Butters briefly filled in as the fourth boy. This eventually fell through, but he has been shown to have a friendly relationship with the other boys since then.