A unit with the Capture or Kidnap skill can drop enemies off at the prison. In Birthright, Orochi performs this while in Conquest, Niles does this instead. In Revelation, either can be used to capture desired enemy units.
To drop an enemy off at the prison, the "Capture" option must be used when Orochi or Niles is near a target they can attack. After a normal battle sequence, if they manage to defeat the enemy, they will drop them off at the prison. After the battle ends, you can visit the prison and inspect the captured prisoners. One of your allied army units (excluding Einherjar, other generic units on your side, and Amiibos) may take a shift at the prison. Pick the "Inspect" option to see your captured prisoners.
The level of the prison will affect both Critical Hit rates and the amount of prisoners it can hold. At level 1, it can hold up to 2 prisoners. At level 2, it can hold up to 4. The maximum amount of prisoners it can hold at any given time is 6 prisoners, which will be at level 3. There are three options after inspecting prisoners; bribe, persuade, or release.
By bribing prisoners, you will give them a set amount of your resources (from your path) and they will work for you without question. The resources they demand are based on the game path and may be discounted depending on whoever is taking the shift. While it can be potentially costly as the Arena will be required in order to obtain the necessary resources quickly, it does save the time of persuading them.
Persuading prisoners is significantly slower but is cheaper compared to bribing them. The level of the unit determines how long it takes to persuade them; for example, a level 3 Outlaw can be instantly persuaded to join, while a level 20 Great Master will take far more attempts. However, this does pay off long-term as it cheapens the bribe cost by a slight amount. When the message "Almost convinced..." appears, the next persuasion will instantly recruit them into the player's army.
Note that only 20 "other" units can be in the army at one time; should this exceed, you will be forced to dismiss one of your units (you will be prompted to update their roster before they are sent off). In the event that you want the unit back, you can buy them back from your logbook, similar to other bonus units.
Enemies with enemy only skills such as Inevitable End and Staff Savant have them automatically removed upon being deposited in the prison. However, enemies with standard class skills even if they cannot normally learn the skill are still retained, making the prison extremely viable for Conquest players.
Prisoner units are generally inferior to main units recruited in the game. They don't have growth rates of their own but rather, is based on the class they are. However, the case is different with captured bosses like Gazak, as he is a unique prisoner, who has a personal growth data of his own, and sometimes may even perform better than some main story units. All prisoners also lack a personal skill as well as being unable to support with other units, limiting them to providing little bonus when aiding another unit in battle. They are limited to class changing, having only one secondary class to change into (barring DLC classes), meaning they can't learn many skills compared to main story units. However, this doesn't mean they are entirely useless. Capturing prisoners allow the player to recruit many units, that appear as an exclusive class from a different route, into their army (like a Berserker in the player's Hoshidan Army). They can also serve as replacement for fallen characters in classic mode, or even increase the player's mobility in maps.
Upon being recruited into the player's army, prisoner units (excluding bosses) become mute like Einherjars, despite using a random set of voice clips in the chapter prior to their capture.
Players have more options to capture enemies in these routes because of their ability to grind in maps before proceeding with the story, and if they are in need of units. Previous completed maps can always be scouted that will spawn random enemies. From here, players can capture and persuade many prisoners to join their ranks. Enemies in these routes however, almost bring nothing to the table and must be leveled to learn their abilities. It is most noted to capture them from the story chapters as they'll have average stats that balance with the player's progression. Many of their stats from the scouted maps (regardless of how far the player progressed) are almost abysmal. Although, capturing them in scouted maps that takes place in earlier chapters allow them to appear as low levels, so players can train and learn their skills accordingly.
Though, limited due to the inability to grind in previous maps on this path, Conquest is where enemies are much more useful to capture as many of them encountered come equipped with exclusive skills outside of their class sets (such as a General with Countermagic). They are worth more capturing on higher difficulties (preferrably Lunatic mode) as they'll come equipped with more exclusive skills, and have higher stats than average that makes up for their poor growths. If recruited from the logbook to use in either Birthright or Relevation, they will perform much better than any generics obtained from those respective paths, and sometimes even rival with many main story units.
Names for prisoners are randomized after being captured. Their names will correspond depending on which side their class is exclusive to. For example, a captured Cavalier belongs to Nohr, so he will be given the name Roland, and a captured Archer belongs to Hoshido, so he will given the name Yamato. The generic cavalier cannot be given a name that would be given for a generic archer, and vise-versa. This also applies to female generics such as Maids, Falcon Knights, etc.
While the list is incomplete at the moment, these are a list of names that can be given randomly for a captured generic unit:
- The captured units have unique names, but still use generic portraits.
- They will keep the same portrait they had when captured if they are changed into another class. In addition, they retain the red color palette in the prison.
- An easy trick to find out names of the prisoners before visiting the prison in the Castle is by capturing as many units as possible in battle until it exceeds the limit the prison can hold. The game will prompt the player to release one of the prisoners (or the unit that was just captured). Once prompted, the player can see the names their prisoners were given before the battle is over.
- When the player battle saves before capturing a unit, the name will always be randomized for that last captured unit. This makes a good trick for players that aren't satisfied with the name given, and reset the game to recapture that unit until they find a name suitable for that prisoner.
- The profile description for all generics will be described as: "A soldier who fights for his or her own reasons." This also applies to generic units from the Einherjar Shop.
- Prisoners will act as usual Einherjar units once they have been recruited, showing the silent treatment when they are in action even if he/she was captured prior when their voice clips were present. This does not affect bosses as they are unique prisoners and will retain their voice clips.
- After a certain point, bosses that originally appear in a base class who are captured in their promoted class retain their base class model when the player visits their prison cell. For example: Gazak captured as a Berserker will retain his Fighter model when the player visits him in the prison.