Parallel Kingdom was a mobile location-based massively multiplayer game that placed a player in a virtual world on top of the real world, based on the player's GPS location. Parallel Kingdom was the first location-based RPG for the iOS and Android platforms. The game was developed by PerBlue, a privately held mobile and social gaming software company founded in 2008 and based in Madison, Wisconsin. In 2011, the game's user base surpassed 1,000,000 players worldwide. The game closed on November 1, 2016. The game was set in a virtual world or "Parallel Kingdom" where users claimed their territories based on their GPS location or by making friends who could invite them to travel to new places. Parallel Kingdom was a freemium game, meaning it was free to download and play, but players had the option of purchasing premium content. Overview Gameplay Parallel Kingdom is a territorial RPG with a diverse range of ways to play. In order to travel around the world, a player has the option of using GPS to relocate through their phone or to build in-game flags on unclaimed areas. It has many features that allow for players to focus on various types of gameplay or to choose a unique combination of styles, such as PvE, PvP, Merchant, and Socialite. The PvE side of PK has many different features to it. Players can find a diverse range of NPCs to interact with. NPCs have many behaviours: some are docile, while others will attack you (or anything that happens to get too close) on sight. Some can only be found alone, while others are always in packs. NPC difficulty is determined by a player's equipment level, meaning a player should be able to fight against monsters tailored to their equipment level. However, some enemies may have been spawned by another player in the area; these spawns may potentially be unsuitable for some players. Players choosing to play PvE have the choice trying their luck at exploring Dungeons. Dungeons are challenging themed areas that require a player to go through each and slay the boss(es), which in turn will give them a special reward. Some PvE-oriented players can even choose to avoid fighting altogether, choosing instead to explore or harvest and gather materials, such as wood and stone. PK's PvP gameplay has many styles to enjoy. Players can choose to duel one another, either in controlled city duelling arenas