Fire Emblem: Seisen no Keifu (English: Genealogy of the Holy War) is the fourth game in the Fire Emblem series, released in Japan only on May 14, 1996. It is notable for its large maps and the introduction of both marriage and children to the franchise, not to be revisited again until Fire Emblem: Awakening.
This game has a lot that differentiates it from other games in the series. As opposed to other Fire Emblem games, where the player must seize a single goal to complete a chapter, this game has the player seizing multiple castles per chapter, with much larger maps to compensate. As a result, the game is only 10 chapters long, split into two segments. Captured castles also take the place of shops, arenas, armories, and the convoy that can be found in other Fire Emblem games, with all of them accessible from any allied castle. Promoting units can only be done from the player's starting castle, however. Also unlike other games is the fact that there is no limit on the number of units that the player can deploy on any given map, which is balanced by giving the player fewer controllable units throughout the game.
Another large aspect of the game is the generation system, which determines what units you can control during the second half of the game. The characters paired during Book 1 of the game will have their children controllable during Book 2 with their stats being a hybrid of their parents' stats.