Breath of Fire IV is a traditional console role-playing game with an overhead, isometric viewpoint. The game's camera can be manually rotated by the player up to a full 360 degrees in some instances, though unlike Breath of Fire III it cannot be tilted up or down. The game environment is rendered in full 3D, while character are present as two-dimensional hand-drawn sprites. While moving about the world, players can interact with computer-controlled characters and objects, gain knowledge on the world around them, and gather clues on how to advance the story. Each playable character is given a special "field skill" that can be used to destroy obstacles or solve puzzles outside of battles, which occur randomly in hostile areas or dungeons.
The "Master System" from Breath of Fire III returns, allowing players to customize each character by having them apprentice under different masters found throughout the world. Under their guidance, these characters may gain new skills and special statistic increases by fulfilling certain tasks, such as participating in a certain number of battles, or finding specific items. The fishing mini-game common to the rest of the series also returns, along with the village-building Faerie Town feature from the previous title that allows players to construct a special village that opens new features.
A battle sequence.Battles take place with teams of three characters against any number of enemy opponents. During these combat sequences, the player can choose which characters will perform an action in any order, as well as switch in any available reserve characters from the back row. While positioned in the back row, a character may not participate in battle, but may regain lost health or magic every combat round, as well as become unaffected by any attacks. Battles are won when either all enemies are defeated or all characters in a player's front row are out of health. Each battle yields experience points that go toward earning levels for each character, which in turn grants increased statistics and new skills.
New to Breath of Fire IV is the Combo System, which allows certain spells or skills to be cast in a specific order to gain bonus damage or other affects. Casting two ice spells in sequence, for example, will produce a stronger ice attack, while a fire spell followed by a wind spells with instead create a new explosion-based attack. Combos may also automatically occur in single attacks that have more than one effect.
Like previous games in the series, Breath of Fire IV takes place in a fantasy world inspired by both classical European and Japanese folklore. A number of races resembling humans and anthropomorphic animals populate the land, which carries a predominate medieval and sword and sorcery theme. The world itself is divided into two distinct cultural halves: the Western Fou Empire, modeled after feudal China and East Asia, and the Eastern Kingdoms, with areas resembling both Medieval Europe and Arabia. While both cultures remain at an uneasy alliance following years of turbulent war, the actions of several military officials threaten to once again pull the world apart. Watching over humanity are the Endless, immortal godlike beings who take the form of dragons and control the elements that sustain the world. Much of the plot deals with the central characters' interaction with the people and Endless who inhabit the world. Throughout the game the player will play as Ryu and occasionally play as the game's antagonist Fou-Lu. Fou-Lu is the first Emperor of the Fou Empire and is referred to as a god Emperor. He seeks to rule the world as a god, however, he needs Ryu to accomplish his goal.