Hollow Regalia, Vol. 2 (Manga): Volume 2

In a world where Japanese people were almost completely wiped out...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 a Moujuu. Yahiro manages to talk with her--until they find themselves under siege by RMS. Whoever this girl is, she matters. Now, if only she and Yahiro could get on the same page...!