Hollow Regalia, Vol. 2 (manga)

Tasked with taking out the leader of the Moujuu, the Kushinada, Yahiro and his party have ventured deep into the ruinous 23 Wards. They're greeted by two shocking sights: a vegetable garden and a Japanese girl riding on a Moujuu's back. Although the girl is wary of them, Yahiro manages to talk with her--that is, until a thunderous noise splits the air...