Fire Emblem Gaiden is the second entry in the Fire Emblem series of strategy RPGs. Set in the same game world as it's predecessor, the events of Fire Emblem Gaiden actually take place on a different continent and thus have no bearing on the first game's narrative. However, several characters from the original game do make return appearances. Released two years after the first Fire Emblem, Gaiden is the second and last game in the series to be released on the Nintendo Famicom.
The game follows two protagonists, life-long friends Alm and Celica, over the course of five chapters and takes place in two kingdoms on the continent of Valencia: Rigel and Sofia. The world map is slowly revealed for players to traverse through the game's five chapters. Over the course of the game, it is revealed to both Alm and the player that he is actually the prince of Rigel, whereas Celica is both the princess of Sofia and a priestess of the goddess Mila. Fire Emblem Gaiden was the first game in the series where more than one main character could promote. Alm begins the game as a Fighter before eventually promoting to Hero. Celica is a Priestess, and she promotes into Princess.
While keeping the main formula intact, Gaiden added a series of major and minor changes to the gameplay. The most notable of which is the addition of branching classes. Players have the option of multiple classes to choose from when promoting characters. Also, spells in the game are not considered weapons; they are instead learned by leveling characters up. Main weapons never break and only special weapons have the need to be equipped.
While the number of differences with the original Fire Emblem's gameplay was large, the following titles reverted to the first game's formula to focus more on strategy. However, both Fire Emblem: The Sacred Stones and Fire Emblem: Awakening both feature overworld maps and branching promotion systems much like the ones seen in Gaiden.