League of Legends takes place in the fictional world of Runeterra. In Runeterra, the champions of League of Legends are a collection of heroes and villains who have a variety of backstories, often related to the political struggles of the various countries of the main continent of Valoran. Additionally, some champions are extraplanar and come from worlds other than Runeterra, but are visiting for their own purposes. These champions sometimes clash with each other, roughly reflected in the gameplay of League of Legends.
Below are the characters on the site that cosplayers have depicted.