OVA
Description
Sanae Nagatsuki is a 16-year-old human high school student with brown eyes and short brown hair, typically adorned with a white headband. She stands 154 cm tall. Her casual attire often includes a green or pink spaghetti-strap tank top paired with a blue plaid skirt, red sneakers, and white socks, while school scenes depict her in a standard Japanese seifuku uniform. She resides alone in a large property, with no explanation for her parents' absence, and owns a pet dog named Alex, who exhibits jealousy toward her obsessive interests.

Initially self-described as introverted and shy, her childhood friend Eiko Aizawa views her as "natural." Upon meeting Ika Musume (Squid Girl), Sanae develops an intense, obsessive crush, leading to persistent stalking. This obsession fuels extensive photography of Ika Musume, beginning with cosplay outfits and expanding to candid moments, amassing a large collection of photos and memorabilia. She exhibits masochistic tendencies, deriving pleasure from Ika Musume's violent rejections involving tentacle attacks or ink sprays. Despite this dynamic, she demonstrates self-sacrificial loyalty, such as wearing a shrimp costume to aid Ika Musume during a health crisis when prompted by Eiko. She experiences jealousy toward others close to Ika Musume, particularly Kiyomi Sakura, though she eventually accepts their relationships as natural.

Her abilities include exceptional endurance and agility, primarily activated during pursuits related to Ika Musume. She achieves feats like swimming long distances using the butterfly stroke to retrieve objects and sprinting across sand in flip-flops at near-Olympic speeds. Repeated exposure to Ika Musume's tentacle attacks hones her reflexive dodging skills. Rigorous training from Chizuru Aizawa grants her the strength to chop through 15 tiles. However, her physical prowess diminishes in non-Ika-related contexts, like tiring quickly during casual badminton.

Her character development involves shifting from possessive jealousy toward cautious acceptance of Ika Musume's friendships. A pivotal moment occurs when Kiyomi discovers Sanae's extensive trove of Ika Musume merchandise, including handmade items like a body pillow. This encounter fosters mutual understanding, leading Sanae to gift her entire collection to Kiyomi and establish a genuine friendship. She gradually reduces physical advances toward Ika Musume, focusing instead on supportive, albeit intense, admiration. Her hobbies include cosplay and sewing, though she struggles with general housework and cooking. She attempts but fails to obtain a scooter license due to distraction from traffic signs resembling tentacles.

Additional trivia notes her financial capability to pursue obsessions, such as purchasing all Ika Musume-themed merchandise from the Lemon Beach House or buying gaming consoles despite no personal interest. She occasionally assists at the beach house during staffing shortages. Her quirks include displaying Ika Musume's photo during meals for "improved appetite" and claiming to detect Ika Musume's unique scent in public spaces.