Soldiers are the weakest units in Ogre Battle 64, but they are also critical to building an effective army. By winning battles against the enemy, soldiers can promote into fighters and amazons. Promoting soldiers is the only way to recruit new, non-unique, members into your army, so you need to learn to use soldiers effectively as quickly as possible.
I recommend promoting as many soldiers as possible before the end of chapter two. You can continue promoting soldiers for the entirety of the game, but it becomes harder to do in the second half of the game because you will be facing stronger units.
On the other hand, make sure you give non-soldier units plenty of time on the front lines. An army full of fighters and amazons will make it difficult to complete the game; by chapter three you should have many several units with advanced classes.
Like many of the advanced features in Ogre Battle 64, the game never fully explains how to promote soldiers. For a long time, I thought soldiers promoted randomly after winning battles, but there is nothing random about it! You can control how quickly soldiers promote, and you can decide if you want a fighter or an amazon.
Earning Soldier Experience
Soldier experience is a hidden stat for every non-unique human character class capable of leading a unit. The soldier experience of the unit leader determines when a soldier will promote. The soldier experience stat begins with a value of zero; when the value reaches 100, one soldier will promote. After one soldier is promoted, the soldier experience value will return to zero.
The only way to gain soldier experience is by winning battles while at least one soldier is a part of the unit.
When you win a battle, each individual soldier alive at the end of the battle will gain two soldier experience for the unit leader.
In other words, one full soldier unit (three soldiers) awards six soldier experience for winning a battle. A single soldier awards two soldier experience for winning a battle. If you win a battle with the maximum number of soldiers (four units of three soldiers; twelve soldiers), the unit leader will be awarded 24 soldier experience.
A unit that consists of a unit leader and four complete soldier units can promote a soldier after winning five battles. I have found that a great way to promote soldiers is to order a unit with four complete soldier units to finish-off leaderless enemy units.
You can only earn soldier experience when fighting against an enemy unit during a mission. Training matches and neutral encounters (finding beasts in the wild) will not award soldier experience.
Losing Soldier Experience
Promoting soldiers is a tricky business. If you aren’t careful, you can accidentally lose all of the soldier experience you have worked hard to earn.
Only a unit leader can earn soldier experience. If the leader loses their leader status for any reason, that leader will also lose any soldier experience he or she had gained.
Changing the unit leader – even temporarily – will reset soldier experience to zero. Disbanding the unit – even if you immediately recreate a new unit with the same leader and different soldier units – will reset the soldier experience to zero.
A unit leader cannot earn soldier experience if there are no soldiers in the unit. If all of your soldier units die in battle then the soldier experience value will be reset to zero.
You must be extremely careful while trying to promote soldiers!
Fighters and Amazons
If the unit leader is male, all soldiers in the unit will promote to the fighter class. If the unit leader is female, all soldiers in the unit will promote to the amazon class.
You can reverse the outcome by equipping the unit with an ansate cross. You are provided one ansate cross at the beginning of the game, and you can earn another by completing a simple side quest at the Zenobian Border.
When a unit carries an ansate cross, all soldiers that are promoted in that unit will be the opposite gender of the unit leader.
In addition, units will not promote if the basic equipment for the fighter or amazon class is not available. You can buy extra sets of equipment for fighters and amazons on the organize screen.
Centurions are a special melee class available to both male and female units. Centurions are the only non-unique class that can lead a legion, and they perform well in combat. Legions are not useful in most situations due to their reliance on soldiers, so I prefer to use centurions as unit leaders for other units.
The centurion class will not become available until you begin chapter three, and only unit leaders who have promoted seven or more soldiers are eligible to become centurions. If you are interested in having a centurion, make sure to focus on having a single unit leader promote your soldiers.