The overarching story follows the protagonist, a customizable Avatar named Corrin by default, as they are unwillingly drawn into a war between the Kingdoms of Hoshido (their birthplace) and Nohr (their adopted home), and must choose which side to support.

The gameplay, which revolves around tactical movement of units across a grid-based battlefield, shares many mechanics with previous Fire Emblem games, although some elements are unique to each scenario.

[10] A new feature introduced to the series is "My Castle", in which the player is able to create a base for their army, where they can establish shops, buy weapons and items, and interact with allied characters.

During the invasion of Hoshido, the Nohrians spare Hinoka and capture Sakura, while Takumi, whose behavior has become increasingly erratic and violent throughout the war, apparently dies by jumping off of a rampart.

Azura explains that the king of Valla, the dragon Anankos, has plans for humanity's destruction; he is the one who killed and replaced Garon, and he is responsible for Takumi's descent into madness in the Conquest route.

Fleeing Valla with Gunter, who survived his fall into the chasm, Azura reveals that they must unite Corrin's twin families before a natural event which will seal the passage for decades.

When they face Anankos, they are initially helpless, but Ryoma, Takumi, Xander, and Leo feed the power of their Legendary Weapons into Yato, transforming it into the Fire Emblem.

[25] Paid additional content was released alongside the games, in the form of extra levels used to improve the units' strength or gather exclusive resources.

However, Azura's son, Shigure, breaks the illusion and bands the two Kanas' armies together, only to leave them to face Anankos alone with the hidden verse of his mother's song.

[32] The two kingdoms were based upon different cultures: Hoshido was themed after Japan, while Nohr used a Medieval European setting similar to earlier Fire Emblem games.

Kozaki did not put much thought into their general appearance, but took care about their clothing so that it was not overtly styled after either Hoshido or Nohr, keeping the neutrality of the player up to the main story decision point.

They were given bare feet due to the animalistic impression Kozaki had after hearing of their strong ties to dragons, along with creating a "hook" for players equivalent to other characters in the game.

[34] The main key artwork, showing the two families together, was described by Kozaki as "a pain to draw" due to their clashing designs, and was the point of much discussion by staff before it was finalized.

This opened up the option for players to run through the game until the crucial decision point in Chapter 6, then buy the alternate routes as downloadable content so they had different choices.

After delivering his work, he then wrote summaries of equal length for Conquest and Revelation, driven by the need to create a high-quality story, partially to surpass his daughter's pressuring expectations, and ended up writing enough script to fill two books.

[39] The game's theme song, "Lost in Thoughts All Alone",[g][40] was written by Morishita, with lyrics by Maeda, and sung by Japanese pop singer Renka, who also provided Azura's in-game singing voice.

[54] Two "starter packs" for the trading cards come with codes that allow players access to the characters Marth and Lucina in the game in the form of DLC.

[50][64] Elements of a minigame exclusive to the My Castle area, involving "petting" a chosen character's face on the touch screen to build up affection, was also removed from the western versions.

[50] These changes, among others pointed out through comparisons by fans between the English and Japanese versions, generated controversy over the Internet in the wake of the game's release, culminating in complaints being sent directly to Nintendo.

[77] Martin Robinson of Eurogamer praised the game as a sound continuation of the mechanical improvements of Awakening: he positively noted the grey morality of the characters and story, and singled out Conquest as the "cooler" of the two physical versions due to its challenge and cast.

[76] Chris Carter of Destructoid called Birthright's story "relatively open and shut" despite keeping complex character relationships intact, while generally citing it as the best starting place for series newcomers.

[73] Javy Gwaltney of Game Informer called the story of Birthright "a surprisingly dark tale", praised the improvements made to the gameplay over Awakening, and was overall positive despite some criticism of its poor tutorial systems.

[75][84] Carter found Conquest a much tougher experience from a gameplay perspective, being geared towards dedicated tactical battles within pre-set limits, while finding its story more intriguing than that of Birthright.

[73] Gwaltney called Conquest a "dark fantasy epic" that asked difficult moral questions, and generally cited the gameplay as harder and consequently more rewarding than that of its counterparts despite sharing tutorial deficiencies with Birthright.

[82] Jose Otero, writing for IGN, frequently noted the game's challenge, while generally sharing his praises with Sullivan's review of Birthright, including slow online elements.

[86] Peter Brown, reviewing the game for GameSpot, praised the gameplay variety and the characters' development and meaningful use in battle, while critiquing the plot for being "fairly middle of the road" and did not like the lack of optional side missions.

[87] McElroy and Frank referred to Conquest as the more challenging of the two physical releases, an opinion shared by Carsillo and Sheridan: the latter added that the game would not make players feel like a hero.

[74] Corriae was highly positive about the game: while finding the initial premise rather contrived, she greatly enjoyed the resultant drama and found the story better than that of Birthright and Conquest.

[83] Sullivan of IGN greatly enjoyed the combination of characters and gameplay from Birthright and Conquest, but shared her opinion of the central plot device with Corriae.

[10] Carsillo found Revelation the most satisfying due to the obscuring of key plot points in the other versions despite Birthright and Conquest offering greater character insight, along with positively noting its gameplay balance between the two physical releases.