Gankyuu (頑丘) is a youjyuu hunter who helps Shushou ascend Mt. Hou. Though he was born in Ryuu, civil strife forced his parents out of Ryuu, where they were removed from the census records and Gankyuu's family became vagrants. As a result, he belongs to no kingdom, having lived his life as an itinerant traveller.
During his first meeting with Shushou, she forcibly hires him to be her bodyguard when she insists on ascending Mt. Hou on a pilgrimage to become the next ruler of Kyou. Unable to persuade her otherwise, he reluctantly goes along with her, initially believing she will be intimidated into giving up upon reading the foot of the mountain because she had become entirely on the impulses of a child. When she is undaunted and demands that they continue, he follows her in order to prevent her from getting hurt.
Because of Gankyuu's experience as a demon hunter, he is familiar with the dangers of the Yellow Sea surrounding Mt. Hou and Shushou usually accepts his explanations for most of his actions, despite expressing some irritation at others. The duo are joined early on by Rikou, a young man from Sou, who befriended Shushou before she hired Gankyuu as her bodyguard and decides to come along to protect Shushou as well.
Though Shushou listens to Gankyuu's orders, his pragmatism towards surviving in the Yellow Sea, where he puts the survival of his employer and himself above that of the group, grows to frustrate Shushou, who knows that Gankyuu's reasons cannot be faulted. Despite his aloofness, Gankyuu does not deliberately withhold knowledge or advice from other travellers; he merely does not bother to tell people who are not willing to ask.
- Tonan no Tsubasa - chapter 38, Eugene Woodbury's translation
Gankyuu was born in Ryuu. Driven out of the kingdom by civil strife, his parents were stricken from the census records. They relocated to En, except that the Kingdom of En existed for the people of En and the refugees were left to observe the lives of its blessed subjects while sleeping at the side of the road. They could hope for no land or children of their own. As vagrants, they were cut off every aspect of society.