A lot of characters are born of the Story Team or the Design Team.
Number 10 was born from a single player decision during the World Championships for the CCG in 2000.
During the finals of that World Championship, the Air Dragon was recruit using The Sacred Temple of the Phoenix ability to produce 7 gold but the card gained the Shadowlands trait. Between that and the 2 copies of Evil Portents that were played in the finals by the Phoenix player Justin Walsh, it was decided to permanently taint the Air Dragon which gave the dragon control over the Lying Darkness, the Goju and Ninube. That version of the Air Dragon became the Shadow Dragon.