Days with My Stepsister

Days with My Stepsister (義妹生活, Gimai Seikatsu) is a Japanese mixed-media project created by Ghost Mikawa. It started with a YouTube channel created in April 2020, with its first video uploaded on May 1, 2020. A light novel series is written by Ghost Mikawa and illustrated by Hiten. The series began publication by Media Factory under their MF Bunko J imprint in January 2021. A manga adaptation by Yumika Kanade began serialization online in Kadokawa Shoten's Shōnen Ace Plus in July 2021. An anime television series adaptation produced by Studio Deen aired from July to September 2024.

Days with My Stepsister
First light novel volume cover, featuring Yūta Asamura and Saki Ayase
義妹生活 (Gimai Seikatsu)
Genre	Romantic comedy[1]
Light novel
Written by	Ghost Mikawa
Illustrated by	Hiten
Published by	Media Factory
English publisher	NA: Yen Press
Imprint	MF Bunko J
Demographic	Male
Original run	January 25, 2021 – present
Volumes	13
Manga
Written by	Ghost Mikawa
Illustrated by	Yumika Kanade
Published by	Kadokawa Shoten
English publisher	NA: Yen Press
Magazine	Shōnen Ace Plus
Demographic	Shōnen
Original run	July 16, 2021 – present
Volumes	4
Anime television series
Directed by	Souta Ueno
Written by	Mitsutaka Hirota
Music by	Citoca
Studio	Studio Deen
Licensed by	Crunchyroll
Original network	AT-X, Kansai TV, Tokyo MX, BS11
Original run	July 4, 2024 – September 19, 2024
Episodes	12

Premise

After his father's remarriage, Yūta Asamura finds himself getting a new stepsister, Saki Ayase, who happens to be the hottest girl in his grade, and living together with her. Having learned the important values about man-woman relationships, seen through their parents as they carry the scars of their parents’ troubled divorces, and in order to not cause discord in the family, Yūta and Saki promise to keep a reasonable distance from each other, not to be too close or too opposing. Saki, who is longing for affection from her family and worked in solitude for their sake, does not know how to depend on others, while Yūta is bewildered at how to properly connect to Saki as her older brother. Feeling somewhat similar, the two of them gradually feel comfortable living together. But what starts as cautious camaraderie blossoms into something deeper from shared experiences. Is it admiration, familial love, or something more?

Characters

Yūta Asamura (浅村 悠太, Asamura Yūta)

Voiced by: Kōhei Amasaki

The protagonist of the Days with My Stepsister series. He is Saki's step-brother and a second-year high school student. He works part-time at a bookstore. Although he and Saki initially have a distant relationship, he develops feelings for her, triggered by the sight of her during a visit to the pool.

Saki Ayase (綾瀬 沙季, Ayase Saki)

Voiced by: Yuki Nakashima

The female lead of the series. She is Yuuta's step-sister and a second-year high school student. She has the appearance of a gyaru. She later works part-time at the same bookstore Yuuta works. Although she and Yuuta initially have a distant relationship, she develops feelings for him, triggered by him turning down her offer to have sex with him and talking about their issues about their former mother/father.

Tomokazu Maru (丸友 和, Maru Tomokazu)

Voiced by: Daiki Hamano

Yuuta's friend at school. He is a member of the baseball team and an otaku.

Maaya Narasaka (奈良坂 真綾, Narasaka Maaya)

Voiced by: Ayu Suzuki

Saki's friend at school. She is always cheerful and meddlesome. She got increasingly involved with Saki because she could not stand to see her isolated, and later became her friend.

Shiori Yomiuri (読売 栞, Yomiuri Shiori)

Voiced by: Minori Suzuki

A university student who works part-time as a senior to Yuuta at the bookstore.

Taichi Asamura (浅村 太一, Asamura Taichi)

Voiced by: Kōhei Amasaki (voice comic), Chikahiro Kobayashi^[2] (anime)

Yuuta's father and Saki's new step-father. After divorcing his ex-wife for various reasons, he re-married to Akiko. He has a good relationship with Yuuta and Saki.

Akiko Ayase (綾瀬 亜季子, Ayase Akiko)

Voiced by: Eriko Hara (voice comic), Reina Ueda^[2] (anime)

Saki's mother and Yuuta's new step-mother. After divorcing her ex-husband, she worked tirelessly to provide for Saki until she re-married to Taichi. She was a gyaru during her high school years.

Kaho Fujinami (藤波 夏帆, Fujinami Kaho)

Voiced by: Atsumi Tanezaki^[3]

Keisuke Shinjō (新庄 圭介, Shinjō Keisuke)

Voiced by: Ryōhei Arai^[3]

Eiha Kudō (工藤 英葉, Kudō Eiha)

Voiced by: Mie Sonozaki^[3]

Media

YouTube channel

While writing several works, author Ghost Mikawa learned of the existence of a reader who had a request to "deeply dig into the daily life of the characters".^[4] He was interested in seeing what would happen if he tried to write an unusual work, and decided to write a story depicting the relationship between step-siblings.^[4]

Regarding the production of the videos, Mikawa is the original author of the Gimai Seikatsu storyline, but the script of the story is handled by multiple writers.^[5] According to Mikawa, the writing style of each writer is shown in each script, so it is often taken as it is.^[5]

All videos on the YouTube channel are subtitled in English, Chinese, Spanish and Vietnamese.^[6]

Light novels

The light novel series is written by Ghost Mikawa and features illustrations by Hiten. It is published by Media Factory under their MF Bunko J imprint, with the first volume being released on January 25, 2021; thirteen volumes have been released as of February 25, 2025.^[7]

At Sakura-Con 2023, Yen Press announced that they licensed the series for English publication.^[8][9]

No.	Original release date	Original ISBN	English release date	English ISBN
1	January 25, 2021[10]	978-4-04-064726-5	October 17, 2023[11]	978-1-97-537203-3
2	March 25, 2021[12]	978-4-04-680326-9	February 20, 2024[13]	978-1-97-537205-7
3	July 21, 2021[14]	978-4-04-680607-9	June 18, 2024[15]	978-1-97-537207-1
4	December 24, 2021[16]	978-4-04-681001-4	November 19, 2024[17]	978-1-97-537209-5
5	April 25, 2022[18]	978-4-04-681361-9	March 25, 2025[19]	978-1-97-537211-8
6	August 25, 2022[20]	978-4-04-681656-6	—	—
7	December 23, 2022[21]	978-4-04-682033-4	—	—
8	April 25, 2023[22]	978-4-04-682404-2	—	—
9	August 25, 2023[23]	978-4-04-682764-7	—	—
10	January 25, 2024[24]	978-4-04-683233-7	—	—
11	July 25, 2024[25]	978-4-04-683793-6	—	—
12	October 25, 2024[26]	978-4-04-684229-9	—	—
13	February 25, 2025[7]	978-4-04-684554-2	—	—
14	June 25, 2025[27]	978-4-04-684885-7	—	—

Spin-off

Ghost Mikawa has also worked on a spin-off, focusing on Shiori Yomiuri and his comment of each anime episode titled, Gimai Seikatsu another days (義妹生活　another days, "Days with My Stepsister Another Days"). It is published by Media Factory under their MF Bunko J imprint.

No.	Release date	ISBN
1	February 25, 2025[28]	978-4-04-684555-9

Manga

A manga adaptation with art by Yumika Kanade began serialization in Kadokawa Shoten's Shōnen Ace Plus online web service on July 16, 2021.^[29]

During their Anime NYC 2023 panel, Yen Press announced that they also licensed the manga for English publication.^[30]

No.	Original release date	Original ISBN	English release date	English ISBN
1	April 26, 2022[31]	978-4-04-112284-6	October 22, 2024[32]	978-1-97-537215-6
2	December 26, 2022[33]	978-4-04-113171-8	January 21, 2025[34]	978-1-97-537899-8
3	September 26, 2023[35]	978-4-04-113914-1	April 22, 2025[36]	978-1-97-539866-8
4	June 25, 2024[37]	978-4-04-115047-4	September 23, 2025[38]	979-8-85-541679-4
5	March 24, 2025[39]	978-4-04-115957-6	—	—

Others

An art book Gimai Seikatsu Hiten ātowākusu (義妹生活　Hitenアートワークス, Days with My Stepsister Hiten Artworks) is published by Kadokawa.

No.	Release date	ISBN
1	September 25, 2024[40]	978-4-04-683800-1

Anime

In July 2022, during the "Natsu no Gakuensai 2022" event for MF Bunko J, an anime television series adaptation was announced. The cast of the YouTube channel are reprising their roles.^[41][42] It is produced by Studio Deen and directed by Souta Ueno, with scripts written by Mitsutaka Hirota, characters designed by Manabu Nii, and music composed by Citoca.^[43] The series aired from July 4 to September 19, 2024, on AT-X and other networks,^[44] with Crunchyroll streaming the series worldwide outside of East Asia.^[45] The opening theme song is "Tenshi-tachi no Uta" (天使たちの歌, lit. 'Song of the Angels') performed by fhána, while the ending theme song is "Suisō no Buranko" (水槽のブランコ, lit. 'Aquarium Swing') performed by Kitri.^[46]

Episodes

No.	Title [47][48]	Directed by [47]	Written by [47]	Storyboarded by [47]	Original release date [49]
1	"I'm Home with a Stranger" Transliteration: "Tanin to Tadaima" (Japanese: 他人とただいま)	Daiei Ando, Mizuki Kobayashi & Naoki Murata	Mitsutaka Hirota	Souta Ueno	July 4, 2024 (2024-07-04)
2	"A Deal and Fried Eggs" Transliteration: "Torihiki to Medama Yaki" (Japanese: 取引と目玉焼き)	Shun Nakajima	Mitsutaka Hirota	Hiroyuki Fukushima	July 11, 2024 (2024-07-11)
3	"Reflection and Revision" Transliteration: "Hansha to Shūsei" (Japanese: 反射と修正)	Souta Ueno, Taro Kubo & Naoki Murata	Mitsutaka Hirota	Souta Ueno	July 18, 2024 (2024-07-18)
4	"Tendencies and Strategies" Transliteration: "Keikō to Taisaku" (Japanese: 傾向と対策)	Daiei Ando, Shun Nakajima & Naoki Murata	Hana Yamada	Daiei Ando	July 25, 2024 (2024-07-25)
5	"A Late Show and the Real Deal" Transliteration: "Reitoshō to Nayatsu" (Japanese: レイトショーとガチなやつ)	Mizuki Kobayashi	Megumi Sasano	Mizuki Kobayashi	August 1, 2024 (2024-08-01)
6	"Sweet & Sour Pork and Rain" Transliteration: "Subuta to Ame" (Japanese: 酢豚と雨)	Shintaro Ito	Hana Yamada	Souta Ueno	August 8, 2024 (2024-08-08)
7	"Feelings and Summer Vacation" Transliteration: "Kanjō to Natsuyasumi" (Japanese: 感情と夏休み)	Souta Ueno & Taro Kubo	Mitsutaka Hirota	Hiroyuki Fukushima	August 15, 2024 (2024-08-15)
8	"A Response and Hot Milk" Transliteration: "Henji to Hotto Miruku" (Japanese: 返事とホットミルク)	Hamana Takayuki	Megumi Sasano	Mizuki Kobayashi	August 22, 2024 (2024-08-22)
9	"Stepsister and Diary" Transliteration: "Gimai to NikkI" (Japanese: 義妹と日記)	Souta Ueno & Mizuki Kobayashi	Mitsutaka Hirota	Souta Ueno	August 29, 2024 (2024-08-29)
10	"Relations and Regrets" Transliteration: "En to Miren" (Japanese: 縁と未練)	Shun Nakajima	Hana Yamada	Shun Nakajima	September 5, 2024 (2024-09-05)
11	"Brother and Sister" Transliteration: "Nii to Imōto" (Japanese: 兄と妹)	Shintaro Ito & Daiei Ando	Mitsutaka Hirota	Hiroyuki Fukushima	September 12, 2024 (2024-09-12)
12	"　　and　　" Transliteration: "　　to　　" (Japanese: 　　と　　)	Souta Ueno, Mizuki Kobayashi & Shintaro Ito	Mitsutaka Hirota	Souta Ueno	September 19, 2024 (2024-09-19)

Reception

In the 2022 edition of Takarajimasha's annual light novel guide book Kono Light Novel ga Sugoi!, the novel series ranked 7th in the bunkobon category, and 3rd in the new work category.^[50] By January 2024, the series had over 600,000 copies in circulation.^[51]

See also

• My Friend's Little Sister Has It In for Me!, another light novel series by the same author