From Hundred Scans:
In a world where humanity stopped progressing and started heading toward ruin, The Superior, Akane and her group head toward India to find out about humanity's difficult future conclusion. At a village they stopped by at Akane accepts a request to defeat a Youma, at the mine where the Youma is said to reside the group encounter a young man. He has no feet, he has no "orb" which gives people their identity in this world. He is a prince of the country of Sai. He is the lesser part of a pair of half-identical twins. Akane suggests taking this mysterious young man along with them to India.