Initially inspired by Koushun Takami's 1999 novel Battle Royale, and particularly its 2000 film adaptation, the battle royale game mode is a sub-genre of multiplayer online deathmatch shooters. The mode involves a large amount of players (typically up to 100) skydiving onto a massive map from the skies. Initially, players are unarmed, and once they land, they must attempt to scavenge for supplies and weapons. As time passes, an ever shrinking circle of safety closes in, outside of which the player will take damage or die. This forces the dwindling player count to close in on one another. There is no respawn, and the goal is to be the last player standing. Modes often include solo, duos, and squads (4-5 player teams).
There are also games which focus solely on training and practice like Battle Royale Trainer and Battle Royale Bootcamp, both of which focus on AI bots.
The oldest game to be retroactively identified as a "battle royale" game is Bomberman, which was the first game that had last-man standing battles in a shrinking play zone.
What later inspired the battle royale game genre was the 2000 Japanese film Battle Royale, which was in turn based on a 1999 Japanese novel of the same name. It led to the emergence of a new "battle royale" narrative genre in Japan during the 2000s, with various Japanese films, manga, anime and visual novel games inspired by Battle Royale.
A related video game genre that emerged in the 2000s are battle royale visual novels, which revolve around a similar battle royale narrative premise. Examples include Fate (2004), Dies irae (2007), Zero Escape (2009), and Danganronpa (2010). Square Enix's action RPG title The World Ends with You (2007) also has a similar battle royale narrative premise.
Fictional battle royale video games are depicted in the 2009 manga series Btooom! (which in turn was inspired by the Japanese film Battle Royale), and the light novel series Sword Art Online in 2010. Btooom was later adapted into a battle royale mobile game, Btooom Online, in 2016.
The battle royale game mode later emerged as PC mods for Minecraft, DayZ and H1Z1. But it was the early access release of Player Unknown's Battlegrounds (PUBG) in 2017 which elevated the mode's popularity in the gaming community. Later that same year, Fortnite introduced a Battle Royale mode into its game, which catapulted the game into the mainstream.
Battle Royale games such as PUBG, Fortnite, Knives Out, Rules of Survival and Garena Free Fire each received more than a hundred million players, and became some of the most popular games of the decade.