Entarou Houjou, married to San Houjou and father of Shuusaku Houjou, is also Suzu Urano's father-in-law. He works as an aircraft engine engineer at the critical Hiro Naval Arsenal in the wartime port of Kure, supporting Japan's naval operations. Known for his consistently calm, composed, and serious demeanor, he rarely shows anger and maintains a quiet, steady presence within his family.

During intense U.S. air raids targeting Kure's naval facilities, the Hiro Arsenal suffers heavy bombardment. Entarou vanishes amid the destruction, causing his family great distress. He is later discovered alive, though injured, at Kure Naval Hospital, confirming his survival. Following his hospital stay, he returns home and resumes his place in the household. His role underscores the experiences of civilian contributors to the war effort and the familial impacts of wartime turmoil, contributing to themes of resilience and adaptation after trauma.