You won’t kill every enemy you encounter in Mount and Blade II: Bannerlord. A handful of them may survive the battle, and when you grab them, they become your prisoner after the end of the engagement. You have the option to sell them to into slavery, giving your army plenty of coins to make your way into the world. However, for those who want to add to their army and expand their numbers, can you recruit them?
You need to do some waiting until they’re available to join your party. After you capture them, you can’t immediately have them join up with you. The option won’t be available and is greyed out in the Party menu. Instead, you need to contain them in your caravan and have them remain as your prisoner for a few days. Eventually, you should see a red exclamation point appear on the party member icon in the lower left-hand section. Click on it, and go to the prisoner section of your menu.
All of the prisoners currently, your party should be listed in that area. Click on them, and you should see an icon where you can now recruit to your party. They will have an upgrade like every other member of your party, and you can freely upgrade them, depending on what troop tree they hail from. You can see what level they are when you hover over them, and their level appears in the middle, as does their character model.
You don’t have to recruit every prisoner you capture. If you have too many troops in your army, you’re better off ransoming them off in the larger towns you visit in the game. The random provides you a decent amount of coin, which is great when you’re starting and can’t contain as many party members in your army. It’s important to view how many people you can have in your party. You won’t be able to contain more than the shown amount because if you do, your army’s movement slows down, and your troops start to leave, over time.
While you’re wandering around Bannerlord, make sure to see how many experience points your character has earned to acquire new skills, perks, and always visit new towns for quests to expand your gold and your renown.