| Term | Definition |
| Mrs. Nakamura | A tailor's widow living in Hiroshima. narrowly escapes disaster when the explosion destroys her house. She and her three children cope with illness and radiation poisoning for years after the bomb, and she faces tremendous difficulties finding work and housing in the years after the explosion. |
| Dr. Sasaki | A young surgeon at the Red Cross Hospital in Hiroshima. treats thousands of the dying and wounded after the bomb, and eventually operates on Miss Sasaki's fractured and infected leg. After the war, he studies radiation sickness and other effects of the bomb. |
| Father Kleinsorge | A German Jesuit priest living in Hiroshima. comforts many of the dying and wounded, even as he falls prey to radiation sickness. He helps Miss Sasaki recover her will to live and eventually become a nun. In the years after the war, he becomes a Japanese citizen and takes the name Father Makoto Takakura. |
| Mrs. Sasaki | A young clerk who works in a tin works factory. becomes trapped in the wreckage of a factory when a bookcase crashes onto her. For weeks she receives no real medical care for her leg, which is badly fractured and infected, and she remains crippled for the rest of her life. After the war, with the guidance of Father Kleinsorge, she becomes a nun, Sister Dominique Sasaki. |
| Dr. Fujii | physician whose clinic topples into the water when the bomb strikes. He, like other doctors in Hiroshima, is too badly injured to help anybody else. Though apparently unaffected by radiation, he falls victim to a sudden, mysterious illness years later. |
| Rev. Tanimoto | A Methodist pastor living in Hiroshima. Mr. Kiyoshi helps bring many of the nameless dying and wounded to safety as fires rage around the city. In the years following the war, he becomes a staunch peace activist and tours America giving speeches and appearing on television. |