Trivia / Washio Sumi Is a Hero

• Actor Allusion: Sonoko had a dream where Sumi became an Idol Singer. Sumi's voice actress, Suzuko Mimori, is famous for voicing Umi Sonoda, a (school) idol who shares a lot of traits with Sumi herself.
• Portmanteau Series Nickname: "WaSuYu" is the official series portmanteau.