Chizuru Aizawa manages and cooks at the Lemon Beach House restaurant. As the eldest Aizawa sibling, she assumed parental duties for her sister Eiko and brother Takeru after their parents' early loss, becoming both caretaker and household authority. She has waist-length indigo hair and indigo eyes, though her eyes typically stay closed. Taller than her siblings, she wears the restaurant uniform and favors practical clothing like shorts over skirts or dresses. Her demeanor remains calm, patient, and reserved, often smiling as she tolerates minor disruptions like Ika Musume’s antics—unless they endanger her family or business. This placid facade hides extraordinary capabilities and a fearsome presence when provoked. Threats to her siblings, the restaurant, or comments about her weight trigger this shift: her eyes open, radiating a menacing aura that intimidates others, earning descriptions like "terrifying," "creepy," or "not human." Chizuru’s abilities exceed normal human limits, nearing near-flawless proficiency. She possesses exceptional strength, agility, and reflexes surpassing even Ika Musume’s tentacles—she can snap them barehanded. Additional skills include sensing moving objects without sight and tearing clothing with one touch. A military background explains these talents, which she reserves strictly for protecting family or business interests. With Ika Musume, she blends tolerance and subtle manipulation. After Ika damaged Lemon Beach House, Chizuru let her work there, treating antics as games within boundaries while occasionally testing the squid girl’s capabilities. Though friendly and bubbly with siblings and friends, Chizuru instills deep fear in Ika, deterring invasion plans through intimidation. Lifeguard Gorō Arashiyama harbors romantic feelings for her, but Chizuru shows no overt interest, prioritizing familial duties. Minor traits include weight sensitivity and a hidden competitive streak, evident when she swiftly reclaims arcade game high scores after losses. Secretly, she operates as "Noh Mask Rider Hannya," intervening incognito during events like a beach stage show or volleyball tournament to restore order or aid her sister.