You are a summoner with the special ability to call upon legendary Heroes from different Fire Emblem worlds. In order to save the Kingdom of Askr from destruction, join the Order of Heroes and face a never-ending challenge."
Fire Emblem Heroes — also referred to as FE Heroes — is a Free-to-Play game in the Fire Emblem series that was released on iOS and Android platforms on February 2, 2017. It is a crossover that features characters from across the series as summoned heroes, along with an Original Generation of new characters.
Set in the World of Zenith, you, a Summoner, are called from Earth to assist the Order of Heroes, an organization consisting of Alfonse and Sharena, the prince and princess of the Kingdom of Askr, and Anna, general of the Order of Heroes, in stopping the Emblian Empire, whose princess, Veronica, and a mysterious masked man have invaded several realms in the Fire Emblem universe and are bent on building an army to destroy the Kingdom of Askr. You and the Order of Heroes must gather heroes from many Fire Emblem worlds while stopping the actions of the Emblian Empire.
Towards the end of 2017, Book II of the main story was released with the heralding of patch 2.0. In Book II, Veronica allies with the country of Múspell, ruled by the sadistic king Surtr, after being convinced to by Surtr's strategist Loki. The Order of Heroes joins forces with Fjorm, one of the princesses of Nifl, and enters the conflict to help the losing kingdom of Nifl survive against Múspell, all while trying to find a way to defeat Surtr and stop him from destroying not just Nifl, but the other nations as well. Book II introduced the concept of "Legendary Heroes", special and strong heroes with unique skills that give elemental effects to those with the same elemental blessing. Book II also introduced the Weapon Refinery system, allowing units to be buffed by upgrading the effects of their weapon, or giving them a new weapon entirely and the Aether Raid mode, a new form of player-vs-player in the same vain as the "My Castle" from Fire Emblem Fates.
On December 10th 2018, Book III was released. Book III sees Askr being invaded by the forces of Hel, the Realm of the Dead. Lead by Hel herself, they seek to defeat Askr, forcing the people to fight back against forces long dead, including historical figures. They are joined by Hel's daughter Eir, who is captured by the forces of Askr and joins under orders from Hel to weaken them from within. Along with Book III, Laguz units from the Tellius duology are summonable for the first time, alongside the introduction of four new seasons, and a new summoning event called Mythic Heroes. Book III also saw changes made to the merging system, the introduction of Dragonflowers as a way to boost the raw stats of units, and Duo Heroes, special heroes that consist of a pair (or more) of characters fighting together with a unique ability to them.
December 5th, 2019 saw the release of Book IV, where the Order of Heroes found themselves in Ljósálfheimr, the Realm of Dreams. There, they will befriend Peony, a member of the Ljósálfr, while being menaced by a pair of Dökkálfr, Triandra and Plumeria, from Dökkálfheimr, the Realm of Nightmares. Book IV introduced the Feh Pass, a subscription service feature that gave access to things such as special costumes for certain units on a monthly basis, special monthly quests, and other features.
Heroes simplifies the traditional Fire Emblem gameplay to be more conducive for the mobile format. Maps have been reduced to a 6x8 grid, teams are only made up of 4 characters, there are only 4 types of units in lieu of a formal Character Class system, and there are less stats to keep track of. There are also no elements of randomness in combat, as all attacks are guaranteed to hit and Specials will trigger based on a counter.
Heroes was given an online manga adaptation, A Day in the Life, as a result of its success.
Due to the nature of the game being a crossover from all of the games in the series, spoilers for those games will be unmarked, up to and including Three Houses.