Dungeon Fighter Online (DFO), known in South Korea as Dungeon & Fighter[a] (DNF), is a multiplayer beat 'em up action role-playing game developed and published for personal computers by Neople, a South Korean subsidiary of Nexon and originally published by Hangame in 2005. The game was originally released in South Korea as Dungeon & Fighter, then in Japan as Arad Senki, and then published in China by Tencent. In 2014, Neople began an alpha test of a global version of Dungeon Fighter Online using the last English version hosted by Nexon, which has since ended.
DFO is one of the most played and highest-grossing video games, with over 850 million players worldwide and over $18 billion in lifetime revenue as of December 2021. This also makes it one of the highest-grossing entertainment media products. In addition, the game has received Japanese anime and manga adaptations.
Dungeon Fighter Online is similar to classic 2D side-scrolling arcade hack and slash/beat 'em up games, such as Golden Axe or Double Dragon. Players traverse 2D screens while fighting hordes of monsters. In addition, there are several social aspects to Dungeon Fighter Online, including Guilds, PvP Arenas, and Party Play.
Skills can be designated upon an upper row of hotkeys that the player's decision can further expand. However, a player can choose to input the command to perform a specific skill manually; for example, a Blade Master can decide to press the assigned hotkey for the skill Draw Sword but can also choose to perform its direct input. Directly inputting the skill (done by pressing the arrow keys in a specific sequence and then pressing the basic skill key) makes the skill cost less MP and lowers the skill's cooldown (the time needed to wait to use the skill again) by a small amount. Skills are usually performed separately from regular combos; however, some skills are "cancellable," meaning that those skills can be used in the middle of regular attacks.
Players can choose to be one of 16 classes ranging from Male Slayer, Female Slayer, Female Fighter, Male Fighter, Male Gunner, Female Gunner, Male Mage, Female Mage, Male Priest, Female Priest, Thief, Knight, Demonic Lancer, Agent, Dark Knight, and Creator. In addition, all the classes get various subclasses to choose from that can dramatically alter their gameplay, such as a Slayer that wears cloth and specializes in summoning demons or a Battle Mage that prefers to melee with spears or polearms instead of casting spells and supplements their leather armor with a powerful mana shield.
A spin-off fighting game, DNF Duel, is being developed by Neople, Arc System Works, and Eighting and is set for release in summer 2022. The game essentially takes the fighting game inspirations for Dungeon Fighter Online to its logical conclusion, bringing together several of the original game's diverse playable characters together to duke it out in raw fighting game combat.