The Saint King of Gai had been in the debt of the Ninth Servant, city lord of the Ancient Imperial City, since he was young. He was subsequently taught by the Ninth Servant, resulting in his legendary status in the Crimson Dragon Realm.
His plane could have easily made him the lord of a city. However, he had not done so. Instead, he'd spent his days either traveling the land or training in the Ancient Imperial City. Everyone who knew him saw him as a member of the Ancient Imperial City.
Due to his close relationship with the Ninth Servant and the others, even though they were not related by blood, Xing Kai and Xing Qiu called him their uncle.
The Saint King of Gai nonetheless valued Xing Kai and Xing Qiu very much. Everyone in Crimson Dragon Realm knew that to be true.
The Saint King of Gai did not have any descendants, so he nurtured the Xing brothers as if they were his own.