|Japanese name||長月 早苗|
|Occupation||Student (high-school age)|
|Alex (Pet dog)|
|Anime Debut||Episode 2|
|Manga Debut||Chapter 9|
|Japanese voice||Kanae Itō|
|English voice||Xanthe Huynh (Season 1)
Emily Neves (Season 2)
Sanae Nagatsuki (長月 早苗, Nagatsuki Sanae) is a primary character in the Shinryaku! Ika Musume series.
Sanae Nagatsuki appears to be a high school-level adolescent. She has brown eyes and is a brunette. She usually wears a green or pink-colored tank top with spaghetti straps and a blue flannel-like skirt with red tennis shoes. She wears a white headband on her head.
Sanae is Eiko Aizawa's childhood friend and classmate. She usually sits at the desk behind Eiko's during class.
Unusually for a high-schooler, Sanae lives alone in a large property. No explanation is given for her parents' absence in the series. She owns a pet dog named Alex, and keeps a wardrobe full of cosplay outfits, which were later replaced by memorabilia related to Ika Musume.
Sanae has superb endurance and agility, although these are not demonstrated until later in the series. She can swim the butterfly stroke (in the anime, she appears to have swum a considerably long distance in order to retrieve lipstick thrown by Ika), and by Chapter 216 (OVA 1 in the anime), she is able to dodge Ika's tentacle attacks, having been on the receiving end of them many times previously.
In Chapter 383, Sanae is put through a harsh training course by Chizuru Aizawa, and gains the strength to chop through 15 tiles.
Sanae has an obsessive crush over Ika Musume, much to Ika's dismay. She is constantly taking pictures of Ika, at first in cosplay, then in canon. She often imagines situations in which she would win over Ika's heart, and gets jealous whenever she sees other girls with Ika. Ika does not return Sanae's affections, and is often disgusted by Sanae's attempts to approach her, that she would hit Sanae back with her tentacles and spray her with ink, though Sanae seems to exhibit a strange masochistic pleasure out of this. Nevertheless, when called up by Eiko for a serious errand, such as retrieving a doll (Season 1 Episode 11, or Chapter 108), Sanae is able to keep calm even when around Ika.
Through spying on Ika while shopping, Sanae learns that Ika's favorite food is shrimp. Thus, she cosplays as a shrimp on two occasions to get closer to Ika, although the second occasion was requested by Eiko to help Ika overcome a mysterious squid-only disease.
Sanae eventually learns to accept that Ika's own friends, or at least Kiyomi Sakura, are not rivals for Ika's affection. By Volume 12, Sanae is able to dodge Ika's tentacle attacks, although she also stops attempting to make physical contact with Ika.
Sanae is the most recurring character in Shinryaku! Ika Musume that isn't the titular character or a member of the Aizawa family, appearing in 150 chapters out of a total of 418 (36%), not including omake chapters.