It's Simple,By the end of the game you must have learned 30 skills.you must learn them you can't
choose them randomly when makeing a officer.At the end of the game the ending screen should tell you how many skills you've learned
if you finish the game, there's an ending with music n stuff,
if you watch closely, you'll see a man wearing big hat with a bird in every picture in the ending.
To unlock new portraits here are some of the following things to do
Aquire 50 items
Aquire 100 items
Aquire 150 items
Aquire 200 items
Aquire 5 Animated Events
Aquire 10 Animated Events
Aquire 15 Animated Events
Aquire 20 Animated Events
Aquire all Animated Events
Meet 100 characters in game
Meet 300 characters in game
Meet 400 characters in game
Meet 500 characters in game
Meet 600 characters in game
Meet all characters in game
You only need to meet the person 1 time. So you can unlock in each Scenario
Simple way to unlock the "Legends Scenario" is to have DW5 Game Data saved on your PS2 Memory Card. Then when you beat any other Scenario it will automatically unlock it after the credits.
This "Legend Scenario" has all the warriors from within the game with their respectice Force, without them aging at all.