In video games, a boss is a significantly powerful non-player character created as an opponent to players. A fight with a boss character is commonly referred to as a boss battle or boss fight. Bosses are generally far stronger than other opponents the players have faced up to that point in a game. Boss battles are generally seen at climax points of particular sections of games, such as at the end of a level or stage or guarding a specific objective. A miniboss is a boss weaker or less significant than the main boss in the same area or level, though usually more powerful than the standard opponents and often fought alongside them. A superboss is generally much more powerful than the bosses encountered as part of the main game's plot and is often an optional encounter. A final boss is often the main antagonist of a game's story and the defeat of that character usually provides a positive conclusion to the game. A boss rush is a stage where players face multiple previous bosses again in succession.

An antagonist is a character in a story who is presented as the main enemy and rival of the protagonist.