Players are usually free to choose any title except King or Queen with approval from the Fantasy Master. This does not usually entitle them to a castle or keep. Only the King/Queen’s home for each color is called a castle. The rest are called keeps.
There is only one King and Queen for each color, but there can be an unlimited number of all other ranks.
Each noble wears the color of his faction. He also wears a symbol for his castle or keep. This could be an anything from an animal to a symbol. For example we might have Duke William of the Red from the keep of the Bear or Lady Isis of the Blue from the keep of Stars. Some might refer to these nobility as Duke William of the Red Bear or Lady Isis of the Blue Stars..
If Duke William is the master of the keep of the Bear then there would not be another resident Duke there, but both Lord Allen and Lord Winchester could still be in residence there.
Lords and Ladies are often not of true noble blood but are from lower class births that have risen to greatness through deeds or power.