Marriage and Friendship Seals introduce unique avenues for character development and stat inheritance in Fire Emblem: Fortune's Weave. Marriage, achieved through sustained support conversations between male and female units, can lead to the birth of children units who inherit traits and skills from their parents. These children often possess powerful base stats and unique class options, making them valuable additions to your late-game army.

Friendship Seals, on the other hand, are items that allow two characters who have achieved an A-rank support to swap classes. This means a character can inherit the class and skills of another unit they are close to. This opens up a vast array of possibilities for creating hybrid units with unique skill sets. For example, a strong physical attacker could potentially inherit the healing skills of a Cleric, or a mage could gain access to powerful sword techniques. These mechanics are crucial for optimizing your army for the most challenging endgame content.