Though Nathan pretends around adults and strangers to be an innocent and severly mentally impaired child, when alone with his best friend and hencman Mimsy, Nathan's true shell comes out as a sadistic, manipulative and vengeful child who isn't afraid to lie, cheat or use under-handed tactics to get what he wants. Nonetheless, Nathan's plans almost always backfire one way or another, almost as often from his own error as those of his assistant. When things are their darkest, he'll do whatever it takes to be on the winning team. Nathan considers his worst enemy to be Jimmy Valmer and he has made numerous attempts on his life, as well as that of Jimmy's respective best friend, Timmy Burch.
Every summer, Nathan's two-faced and abusive parents force him to join the other handicapped children at Lake Tardicaca Summer Camp, while they can go on luxurious trips around the world, pretending they can't understand what he's saying because he has Down's Syndrome. To make matters worse, Nathan's team has lost every activity at summer camp for years to the rival Blue Team, lead by Jimmy, which has only fostered Nathan's feelings of bitterness and resentment. He also worked on the side as a steroid dealer during the Special Olympics, and made sure Jimmy was one of his customers.
He teamed up with Princess Kenny and Stan Marsh in favor of the PlayStation 4 - surprisingly enough, the same system of choice as Jimmy Valmer. Any attempts to sabotage the Xbox One team remain undocumented.
More recently, Nathan noticed the changes in the town of South Park and tried to side with PC Principal and the advertisements to his benefit, becoming the new editor of South Park Elementary's Super School News in Jimmy's absence. He worked for Leslie Meyers' agenda in exchange for a loft and a high-class black prostitute named Classi, who betrayed him to help Jimmy save the town. His current status is unknown.
- "Shut up MIMSY!!"
- "I can't stand him, Mimsy. That Jimmy kid makes my fuckin... skin crawl." (Crippled Summer)
- "Uh, my name is Nathan. I'm disabled." (Crippled Summer)
- "I'm sick and tired of your stupidity, Mimsy! You are the biggest idiot I have ever met! And from now on, if I wanna do something, I'm gonna do it myself!" (Crippled Summer)
- "I hate you, Jimmy. I fucking hate you with everything in my entire being. " (Crippled Summer)
- "We hate camp, Mimsy. The singing, the competitions, Jimmy Valmer getting all the chicks. " (Handicar)
- "Let me give you guys a hot news flash: If you want to hurt a crippled kid, you don't break his FUCKING LEGS!!" (Handicar)
- "Let me ask you a question. Do you want to see my dick?" (Handicar)
- "This is very difficult, Mom. But um... You know how every year I go to summer camp? Well, I hate it. I hate it and I don't want to go anymore. " (Handicar)
- "Do you really think all the changes happening to this town are just coincidence? This goes so much deeper than you can possibly imagine, Jim. Everyone's about to learn the truth. And then... There's a war coming. A war, Jim. And I'm just gonna make sure I'm on the right side of it." (Sponsored Content)
- "Did I do good, computer? I think the sponsored content fooled them. I hope I made you happy. Can you see me, computer? Do you know what I'm thinking right now?" (Truth and Advertising)
- "Now listen, everybody. If you're a sheepherder, and there's a snake taking away your sheep, what do you do to the snake? " (Handicar)
- "If you're a sheepherder and a snake is killing your sheep, you just need to have the snake get sued for sexual misconduct."
- "If you're a sheepherder, and a snake is killing your sheep, all you have to do is prove to the sheep that the snake is a completely inferior entity."
Nathan wears costumes for some of the Handicapable events he is forced to attend by his parents.
Though they appear sweet and well-intentioned, Nathan's abusive and selfish parents seek to be rid of him whenever possible so they can have fun without him.
Nathan's only true close friend is Mimsy, who will do whatever Nathan asks... to the best of his limited ability, at least. Nathan nonetheless keeps his companion around - someone has to do the dirty work for him. He has also become a favorite of PC Principal, who believes Nathan's charade.
More strategic allies than friends, Nathan works with Leslie Meyers in order to instill the ads' will on people, eager to be on "the right side" of the coming war.
Nathan's biggest rivals are Timmy and Jimmy, the most popular handicapable kids in the town of South Park. They're fairly nice to Nathan though.
Although she was initially hired for him, Nathan slapped his favorite high-class prostitute, Classi, and she turned on him.
Every year, Nathan gets sent to the same boring camp for Handicapable Kids that he hates... but his parents get a pretty cool vacation out of it. He leads the Red Team, which always loses to the Blue Team, lead by his rival, Jimmy.
- Up the Down Steroid (s08e03; debut)
- Crippled Summer (s14e07)
- Black Friday (s17e07)
- A Song of Ass and Fire (s17e08; cameo)
- Titties and Dragons (s17e09; cameo)
- Handicar (s18e04)
- Sponsored Content (s19e08)
- Truth and Advertising (s19e09)
- PC Principal Final Justice (s19e10)
He was originally slated for a role in the game with Mimsy - their friend icons are in the game's files - but their role is unknown.
- Some say he bares a resemblance to cult comedian Mitch Hedburg, who died in 2005 -- but Nathan bears an even stronger one to Sean Costello, who worked with Matt and Trey on How's Your News.
- Unlike most South Park characters, Nathan's head is seen primarily from the sides and only briefly may look directly forward.
- He and Mimsy are both homages to the Looney Tunes cartoon characters Rockys and Mugsy - a poster for the two appears in his bedroom in "Handicar".
- In Nathan's first two appearances, he is only seen in incidental gear, but his 'main' look is first seen in a blink-and-you-miss-it moment in "Black Friday".
- Nathan uses the word 'retarded' four hundred times a day. (Sponsored Content)
- Nathan seems to have an interest in African-American women. (Sponsored Content and PC Principal Final Justice)