They are a group of Numbered Children, who have numbers attached to their names. Kinrei casted them away to the outlyings regions as the Frontier Guards (辺境警備隊 Henkyou Keibitai). There were many Ayame in the outlying regions, and the Numbered Children were thrown away there to serve as food for them. Upon meeting Rakan, they abandoned their duty as Frontier Guards and became the "Guards of the Sanome Prince".
Miya was the one who changed all the Numbered children's names, so that their names wouldn't be written with numbers in them.