Dark Gathering, Vol. 5

Having captured the spirit of the H Castle Ruins, Keitaro, Eiko, and Yayoi next set their sights on Tokyo's infamous Old F Tunnel. But before they can brave their first Danger Rank S location, Yayoi takes them on a detour to collect another one of her Graduates—the ghost of a soldier who, even in death, could not escape the pain of war.

Volume 5 of the Dark Gathering manga series by Kenichi Kondo.