His full name is Stan Marsh. Out of all of his friends, he's usually looked at as the leader of the group. Overall he is very normal compared to everyone else.Very down to Earth, he also tries to avoid encounters, but he never fully avoids whatever situation he comes across and is forced to see the problem through until it is resolved.
Kyle Broflovski is part of a Jewish family, this sometimes makes him alienated from the rest of his friends who are Catholic. Like his best friend, Stan, he is very down-to-Earth, logical, and intelligent. Because of his seemingly minor to differences, he is constantly tested on his morals and adversity.
Eric Cartman is probably the loudest, most obnoxious, racist, anti-semitic child in the group. He annoys just about everyone in South Park, even his own friends don't really know why they hang-out with him.He even makes of Kyle for being Jewish! He's made fun of for his weight by friends and strangers alike. Although he is not liked by many in South Park, he is the favorite of many fans of the show.
Kenny McCormick is known for being poor and is made fun of by Cartman for it. He wears a signature hood over his face which muffles everything he says, but his friends understand him perfectly. He is infamous for dieing on the show frequently. His deaths are almost always strange, brutal, and unusual. No one really knows how he comes back in the next episode, but it's been a running joke in the series for years!