The 10 Great Families are the direct descendants of the 10 warriors who first came into the Tower with Zahard. They represent the ruling faction in the Tower, and their members are often extremely powerful, meaning that many of them are Rankers.
Another interesting point about these 10 Great Families is that few selected daughters of the family have the chance to become Zahard's Princesses, and gain an enormous authority and power in the Tower.
The Koon family is headed by Koon Eduan. Since Koon Eduan is famous for his lewdness, he is the man with the most wives of the 10 family heads. He has a lot of children, so there is a lot of veiled competion among his children in the family. Too much competition has created the 'official' fights. It is held once a year, with the following rule: 'When the children of Koon become the age of 10, they are to fight each other. The winners are recogized as the true children of Koon.' The winners are recognized as the true children and get the crest of the family, but the losers become the 'abandoned' and do not get the crest.