Chaika: The Coffin Princess Vol. 4 (manga)

A tip from the mysterious Guy leads Toru, Chaika, and Akari to a means of transportation--and the location of one of the heroes of the battle of the Gaz Imperial Capital, Dominica Skoda. But the journey to Dominica's residence is dangerous, and when the trio is ambushed by a group of monsters, they're saved in the nick of time by a mysterious female knight!