Kyle and Cartman are not friends. Although they can be on civil terms, often they'll insult, fight and rip on each other endlessly. Their rivalry and hatred is so intense that both go to extremes to overcome the other, often becoming obsessed over said rivalry. Although Kyle has saved Cartman due to morals and guilt through out the series, (Manbearpig, Jewpacabra) Cartman has only saved Kyle's life (Smug Alert, Imaginationlad) in order to continue insulting, torturing, and humiliating the other. They'd best be considered arch nemesis.
- In Grounded Vindaloop, Cartman refers to Kyle as his "Arch Rival."