single player modes and new characters or items and cosmetics for online modes, all planned to be released typically within a year's period, typically at a discount compared to purchasing each individually. A game could thus offer repeating season passes year after year and generate revenue this way. A related concept to the season pass is the battle pass, first introduced in Dota 2. Within a battle pass are a number of in-game items that a player can earn at various levels of the battle pass, but requires them to complete in-game challenges as to earn the levels within the pass. Some battle passes include a free tier of items but most incorporate a tier that requires purchase of the pass. Battle passes can be cycled like season passes, offering a fresh set of items with new challenges on a regular basis, and supply recurring revenue for a game. From mobile and free-to-play games, gacha games had grown popular in Japan by the early 2010s, based on the capsule toy vending machine concept, with the earliest known system being in MapleStory. In-game, players would earn currency that they could use to earn a random draw from a set of items based on a preset rarities, often with the goal to collect all of a one set of items to gain a powerful in-game reward. While players could earn more currency through in-game actions, typically by grinding, they could also can currency by spending real-world funds into the game. The gacha concept expanded out into loot boxes through the Chinese game ZT Online, and in Western games like FIFA 09 and Team Fortress 2 in the early 2010s; players would earn loot boxes through in-game actions, or which could be purchased through real-world funds, and when opened would contain a variety of items, randomly selected based on rarity. By 2016, numerous high-profile games had included loot box mechanics, but this drew attention of world governments and policy makers, fearing that loot boxes were too similar to gambling, since real-world money could be used to purchase them. Since many of these video games were being aimed at minors, some countries had passed laws banning or restricting games with loot box mechanics due to their gambling nature. Coupled with poor implementation of loot box mechanics in Star Wars Battlefront II and Electronic Arts's FIFA Ultimate Team game mode, loot box mechanics began to