Shogakukan's listing for the 14th volume of Yomi Hirasaka's A Sister's All You Need. (Imōto Sae Ireba Ii.) light novel series describes the volume as the series finale. The volume will ship on February 18.
Shogakukan previously described the previous 13th volume as the "first part" of the final arc, using the word "zenpen" (前編) that is typically only used for the beginning of a two-part or three-part arc. That volume shipped last September.
Yen Press licensed the novel series A Sister's All You Need., and it describes the story:
Itsuki Hashima is a novelist who's hopelessly enamored with the idea of little sisters and is constantly surrounded by colorful characters. A world class genius and love-guru who's beauty almost seems a waste on her. A girl who's constantly troubled by her friendships, love interests, and can't even find refuge in her dreams. A ridiculously talented illustrator. Each of them have as many problems and worries as the next and they never have a dull day together as they play games, travel, and work together.
Hirasaka launched the novel series in 2015, with illustrations by Kantoku (The "Hentai" Prince and the Stony Cat.). Yen Press published the fourth volume last May.
A television anime of the novel series premiered in October 2017. Crunchyroll streamed the series as it aired in Japan, and Funimation streamed an English dub.
Edo launched a manga adaptation in Shogakukan's Sunday GX magazine in December 2015, and ended it last July. Shogakukan published the manga's eighth and final volume last June.