Tatakau Shisho: The Book of Bantorra  

戦う司書 The Book of Bantorra

All the dead people of the world have been turned into "books" stored in the Bantorra library. A boy named Koria Tonisu has had his memories erased and his chest embedded with a bomb. He is sent to kill Hamyuttsu Meseta, the world's most powerful armed librarian. However, he falls in love at first sight with this beautiful woman in charge of the "books," and he gets enveloped in the great war over the library.