A dynamic event system replaces traditional questing, utilising the ripple effect to allow players to approach quests in different ways as part of a persistent world. Guild Wars 2 claims to be unique in the genre by featuring a storyline that is responsive to player actions, something which is common in single player role-playing games but rarely seen in multiplayer ones. The game takes place in a persistent world with a story that progresses in instanced environments. Set in the fantasy world of Tyria, the game follows the re-emergence of Destiny's Edge, a disbanded guild dedicated to fighting the Elder Dragons, a Lovecraftian species that has seized control of Tyria in the time since the original Guild Wars. Guild Wars 2 is a massively multiplayer online role-playing game developed by ArenaNet and published by NCSoft and ArenaNet.