The main gameplay is similar to the main series where the players fight enemies on a 6x8 grid with 4 heroes from Fire Emblem. The players move strategically similarly to the main series targeting enemies based on the the attribute triangle with Sword & Fire beating Axe & Wind which beats Lance & Thunder which beats Sword & Fire.
The Colorless units (Thieves, Healers and Archers) do not have innate advantages over units and instead provide more utility. The maps are based on chapters from Fire Emblem series. Completing levels earns the player gems for each difficulty (Normal, Hard & Lunatic). The currently available chapters can be seen at the List of Fire Emblem Heroes chapters.
When a player summons a hero, they can choose among 5 summoning stones to summon a character with 5 gems in one of 4 categories, represented by red, blue, green and colorless. If the player fails, they can try again for 4 gems among the remaining and it goes down to 3 gems on them. When a hero is summoned, they have a rating of 3-5 stars with more stars being stronger. The 1-2 star versions are obtained from the Special Maps.
When summoning a hero, the player chooses a banner, that last a couple weeks. These banners highlight 4 certain 5 star characters doubling their chances of getting summoned. Also, during a summon, if the player does not get a 5 star character, the rate increases by .5% until a 5 star is pulled or banner ends.
The arena is the PVP mode. On the offense, the player uses a Dueling Sword token per fight. Once selected, the token is spent and the player must choose one of three opponents separated by difficulty. Once selected, the fight begins on a random map. The player is restricted from using a Light's Blessing, so if a unit dies, it cannot be revived. If the player wins, they will get a score based on if the level of units used and the remaining units' health.
The score will be doubled if they use one of the 10 bonus heroes listed before selecting a fight. The goal is to chain up to 7 battles to score the highest possible during the season of 6 or so days. Earning a score of 3000 or greater in a season will give the player 1600 feathers and if the player ranks, they can earn more. The defense team is chosen based on what team is in the first slot with the unit in the leftmost slot being shown when selecting difficulty. Defending for 250+ points earns 400 feathers.
Units can be upgraded from lower stars if the player uses feathers. Higher stars have better stats and growth rates as well as access to better skills. The feather cost between stars increases by a magnitude for every star at the following rates. These can be reduced by merging like units, though they only reduce it by the same amount of feathers as if they were sent home. The benefits are more SP and improved stats if the merged ally was of equal or higher rank.
- 1 to 2 star - 20 feathers
- 2 to 3 star - 200 feathers
- 3 to 4 star - 2000 feathers
- 4 to 5 star - 20000 feathers
The game was surprisingly a big hit. While not as big as Nintendo's other mobile efforts, the game grossed $2.9 million on its first day with around 2 million downloads, according to Sensor Tower. The game is regularly in the top 5 grossing apps in Japan's iOS and United States' Android charts, two of the bigger markets for mobile games. Critics also generally liked it though it isn't as highly