Changes

Originally more of a gimmick character, Kenny was killed in every episode of seasons 1-5, and then died "permanently" at the end of 5. This "permanent death" lasted until season 7, at which point he became a regular character who still died occasionally, though as before with no consequence to future episodes. Between season 5 and 7, Kenny 's soul was "trapped in Cartman's body" after Eric Cartman confused his ashes with hot chocolate. After drinking these ashes, Cartman began having Kenny's memories and speaking his statements. Kenny is considerably poorer than the other boys, with a run-down house governed by parents who frequently abuse alcohol and engage in domestic violence. Despite this he gets along fine with his better-off friends and does not in general get made fun of for his poverty (except by Eric Cartman). He is "voiced" by Matt Stone, though this is of little consequence as everything he says is mumbled incomprehensibly from an over-sized orange parka. The other characters, however, seem to understand him. For the 1999 movie, Kenny removed his parka, revealing his face and blonde hair color, to say "Goodbye, you guys" (this line was voiced by [[Mike Judge]], creator of [[Beavis & Butt-head]] and [[King of the Hill]]). In one episode written after the movie, Kenny's legible speech and face appeared again, though he was wearing different clothes, and it was not obvious that he was Kenny until he had died.

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, although ironicallyhowever, 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, LuanneLianne encourages Eric's obesity, who and treats him like a friend instead of a son and , thus does not discipline 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.

===Leopald Leopold "Butters" Stotch===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.