The Genocide Route (also known as the No Mercy or Max LV Route) is one of three main routes in Undertale, requiring the player to encounter and kill every monster in every area of the game.
Its story and gameplay diverge significantly from the Neutral and True Pacifist routes, with a majority of puzzles already being done for you (implicitly by Flowey), alternate boss fights against Undyne and Mettaton with Sans taking the role of final boss in the Last Corridor, Asgore and Flowey being defeated in a cutscene, and the destruction of the world by Chara.
Upon completion of this route, the game can only be reset by making a "deal" with Chara, leading to the Pacifist Route's ending being permanently changed to suggest they had possessed Frisk.
