Defiance features advanced character customization. Players have the ability to customize everything from the clothes they are wearing to their facial hair style. Players also have the option to be a Human or an Irathient, a humanoid alien species that are similar to humans. There is not a strict class system, and instead allows players to choose from one of four origins, which are veterans, outlaws, machinists, and survivalists. Origins do not affect the abilities, weapons, or outfits the player can choose, and instead just serve as a starting point and background for your character. The game's key feature is its Arkfall Events, which are dynamic events which pit humans, aliens, and monsters against one another in order to obtain expensive alien technology.