Update: Nintendo has now announced that the iOS version of Fire Emblem Heroes will launch on the same day as the Android version.
Original: During today's Fire Emblem Nintendo Direct, Nintendo finally showed off its next mobile game, Fire Emblem Heroes. Pre-registration for the game begins on January 19th, as it launches on Google Play on February 2, 2017, and it'll be releasing on iOS devices on a later date. Fire Emblem Heroes will be a tactical role-playing game, similar to the main entries of the Fire Emblem series, but with smaller maps and more streamlined combat, making the game at home on mobile devices.
Heroes will have a brand new, original story, but it'll feature many characters from Fire Emblem Awakening, Fates, and other Fire Emblem games. Chrom and Lucina, among many others, will be making a return.
The reveal trailer for the game included a detailed explanation of the new combat system. Overall, although some aspects of the core gameplay will change, Nintendo says that the intensity of the battles will remain true to the series. Players will now fight on an 8x6 grid, far smaller than the maps present in the previous games. To accommodate smartphone touchscreens, the movement controls in the game will be very simple, but maps will be particularly challenging and traversing them will require a lot of strategy.
The biggest new addition is Hero Battles, a new form of timed encounter against enemies. Hero Battles are waged against one select hero, usually an iconic Fire Emblem character, who will join your army once they're defeated. The reveal trailer describes them as "truly heroic undertakings," as they are some of the most challenging parts of this new game.
Nintendo is also hosting a "Choose Your Legend" event for Fire Emblem Heroes on its official website. Players can vote for certain characters to be made available in at launch, with special editions of the top voted male and female heroes to be included. My Nintendo members can also rack in some bonus coins by voting. You can cast your vote here.
Source: Fire Emblem Nintendo Direct