Add a feature for adoption

Unlike in medieval Europe, feudal Japan placed nearly as much emphasis on legal/spiritual connections as it did on bloodline, with fates such as Uesugi Kenshin's showing that adopted children could even inherit clan leadership as daimyo -- still exceptions from the rule, but then again, so is the player character in Sengoku Dynasty anyways.

We can already meet or free adult men and women whilst exploring the map, and adding children as refugees or bandit hostages would only add to the world's realism. Upon an encounter such as this, the player could be presented with a dialogue option to either adopt the child as their own, assign them to one of the village families, or send them away.

An easy way to spontaneously create a heir for the player character, whilst simultaneously adding an interesting moral choice to the game and expanding the paths available for players to create/manage their dynasty.