With all of that talk about class and reclassing, and how deeply dependent they are on supports and relationships, let’s talk about how to get your characters friendly with each other...maybe even cause a few romances (or a lot).
As characters fight adjacently or paired on the battlefield, they’ll build up support points, a hidden value that determines how close the characters are. You’ll see hearts appear to indicate that. Outside of battle, the Support option in the menu will occasionally have new conversations for you to trigger. They are oftentimes very interesting reads that let you glean more information about the character, and more importantly, they will build up your character’s support rank. Support starts off at a C rank and caps off at A, A+, or S. Support points can also be built very slowly through various MyCastle events.
Reaching A-rank support between non-Avatar characters will give greater benefits when paired on the battlefield, but once you pass the A-rank, interesting things will happen! For example, once you have decided who you want to marry, reaching S-Rank will allow the two characters to become a wedded pair. Not only will you unlock a Paralogue with the child character , but you will also give those characters their spouse’s classes through use of the Partner Seal.
Two characters of the same gender will instead sometimes be allowed to reach A+ instead, the more platonic version of the S-Rank. However, they function differently. In an S-Rank pair, neither character can S-Rank with any other character (we practice monogamy in this game, you see).
However, A+ Rank supports are a one-way selection.This means that if Takumi reaches A+ with Ryoma, Takumi now gains Swordmaster as a Friendship Seal class, but Ryoma does not gain the Sniper class in return. In order for Ryoma to gain the Sniper class, he needs to A+ Takumi in return. Or, he can go an A+ with Silas to gain access to the Paladin class (in which case Silas will not gain the Swordmaster class in return, he needs to A+ with Ryoma).
Your Avatar cannot A+ support with anyone. So how will they be able to use the Friendship Seal? Actually, your Avatar has the widest range of possible classes through that Seal. Instead of having to A+ support to gain classes, anybody your Avatar reaches A Rank with who is of the same gender as you will give you their classes through the Friendship Seal. There is no reason to not go ahead and reach A Rank with all of your comrades in Fire Emblem! Plus you get to fill out the Support Log too.