So, yeah… it’s… a siscon show.
Earlier today, Fujimi Shobo announced that the anime adaptation of Seiji Ebisu’s Ore ga Suki Nanoha Imouto Dakedo Imouto Ja Nai (The One I Love is My Little Sister But She’s Not a Little Sister) will hit Japanese TV in October. The series was first unveiled in October 2017.
Seiji Ebisu and illustrator Gintarō’s Ore ga Suki Nanoha Imouto Dakedo Imouto Ja Nai launched under Kadokawa’s Fantasia Bunko imprint on August 20, 2016. Six volumes have been released to date, with the most recent shipping to stores on April 20.
Anime-Planet describes the series as:
Suzuka Nagami is a beautiful third-year middle school student who has excellent grades and is the student council president. She wrote a novel about a little sister who dotes on her older brother, and the the novel wins a light novel award. After they discuss the matter, Yuu Nagami is the one who debuts as a proxy light novel author instead of Suzuka, under the pen name Chikai Towano.