Here's a
character with background story from an old campaign Queen&Country:
Juvenile players are picked on by one to be trained as Queen's praetors: assassins, bodyguards and spies, you name it. They all have their own reasons to join, for example one wants to revenge to the Thieve's Guild for killing her master. Players are carefully trained and tested to finally solve some problems which threat the peaceful kingdom of Burgundy. A great example of thoroughgoing character development. (Middle Ages I/Espionage)
Here's
another with magic from other campaign.