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Muramasa Senju
Senju Muramasa.JPG
Kanji 千寿・ムラマサ
Kana せんじゅ・むらまさ
Romaji Senju Muramasa
Pen Name Senju Muramasa
Nickname/s Kuruizaku Kuroikazuchi no Muramasa
Debut (Light Novel) Volume 2, Chapter 3
Debut (Manga) Chapter 12 (partial appearance)
Chapter 19 (full appearance)
Debut (Anime) Episode 6
Appears in Light Novel


Voice Actor (Japanese) Saori Onishi
Personal Info
Gender Female
Age 14
Birthday Jaunary 17th
Blood Type O
Eyes Lavender
Hair Black
Nationality Japanese
Skin White
Battle Power 14,500,000
Work & Relations
Occupation Author
Affiliation Light Novel Industry/Hachiraijin
Middle School
ASCII Media Works
Friends Sagiri Izumi
Elf Yamada
Shidou Kunimitsu
Love Interests Masamune Izumi

Muramasa Senju or Hana Umezono is a light novel author who is also a devoted fan of Masamune Izumi.


Not much is known about Muramasa's early life. Because she enjoys writing, her family nags at her for writing all day long. They are all very economic-minded believing money should be saved and should only be used for a critical moment when you absolutely need to use it. Despite their nagging, Muramasa has held onto her family's advice on money closely.

Despite her vast knowledge on books and writing. Muramasa is not very knowledgeable, or even aware, about her own surroundings. She doesn't use a cash card and is very bad with electronics in general, even touch-panel systems. Oddly enough, she knows how to use a computer just fine.

Senju Muramasa loves reading as more than just a hobby. She believes fervently that it's the best form of entertainment and that with the right book "just for you," it can surpass any anime, games, movie, and even love itself. However, because she believes the book "meant just for her" can't be found in stores, she decides to write them herself. Before her debut as a light novel author, she was a fan of Izumi Masamune's works dating back to his first story as a web novelist. Because she's such an avid reader, she's able to recall many details of all his stories. She has all his stories saved on her computer.

Unlike Elf or Masamune, who write novels for their fans, Senju Muramasa only writes novels for herself. When she was approached to being a professional writer for light novels, she was convinced to become one since she could write without her family nagging her about always writing. Sometime after becoming a novelist, she received a fan-letter that said they would give her book a million points out of a hundred because of how interesting it was. Because of this, her dream is to write a book for herself that would be nothing less than "the most interesting light novel in the world" since such a book is one Masamune writes, by her standards.

She wrote the light novel "The Legend of the Phantom Blade" which is #1 on store shelves, shadowing Elf's sales by over a tenfold. It's so popular, it has been made into an anime twice. However, she does not know this since she doesn't visit the publishing building often and has a monthly allowance of 4,500 yen. The book is still ongoing, but has not seen a continuation due to Muramasa's grudge towards Masamune's genre change. Because of the similarities in writing style, many fans assume incorrectly that Masamune is Muramasa's clone due to their similar writing styles, though in reality, only the opposite is true.

A year before the events of the story, Muramasa wrote stories with similar subjects to Masamune, causing their plans to overlap. Because of this, Masamune was unable to produce a single book. It's implied that this was intentional, but has not been proved yet so far. Because of her disinterest towards others, she doesn't attend end-of-the-year parties, awards ceremonies, or other events.

Through her connections at the publishing house from the editorial department, Muramasa was able to get her hands on a copy of Masamune's latest proposal, but was upset to learn that he was switching his genre to a romantic comedy. She crumples up the proposal and tosses it in the wastebasket and angrily says to herself that she will not accept it. She then used her connections in the publishing house to fill an earlier publication slot for herself, causing Masamune's manuscript to be pushed back a year before it can be released.


Muramasa has black hair (colored purple in the manga) cut short to around her jawline, called a "bob cut." Her eyes are colored lavender. She has a slender figure with large breasts.

She is always seen in a kimono or yukata and classical obi sandals. She carries a small satchel tied to her waist on the back that carries her notebook, pencils, and other writing materials.

Her fingers on her right hand are constantly bandaged from constantly writing to the point of hurting herself.

During her trip to Taiwan, she is wearing a sun-dress and carried around a parasol.


As a novelist, she has no interest in trying to please the readers when writing her novels; only herself. So much so that she doesn't even bother naming her novels, leaving that to the editorial department. When an idea pops into her head, she immediately starts writing and blocks out her surroundings until she is done, regardless of place or time. She has no regard for the other novel writers, regardless of who they are, believing them to be boring and not worth remembering. It's suspected that she was invited to travel to places like Taiwan for her work, but she has no recollection of any such invitations. This is most evident with Elf Yamada as she doesn't even remember her name despite meeting her several times and muttered under her breath how Elf's book, "Bakuen no Dark Elf" was boring. The only writer she ever acknowledges is Izumi Masamune. Her dream is to write as many novels as she can that are "the most interesting in the world" and read them herself.

Muramasa is a huge fan of Masamune's works and was very upset when she learned he was switching his battle genre to a romantic comedy. On their first meeting, she acted cold and cruel to Masamune's dream, hoping to spur Masamune back to writing battle light novel. After both sides have learned of each other's circumstances, she dropped her cruel act and revealed to not only be in love with his work, but in love with him as a person. Despite being turned down, it seems Muramasa has not given up Masamune. She is constantly at odds with Elf, whom she considers a love rival for Masamune'a affections.

Despite her constantly uninterested appearance, she is actually very shy and girly. She doesn't like wearing bikinis, feeling it exposes too much skin. She is very upfront in her desires to get closer to Masamune, being one of the rare few times she will smile at him. Muramasa doesn't trust Elf and is often irritated or angered by Elf's advancements towards him.


Masamune Izumi

Muramasa is a long-time fan of Masmune's works since his first web novel. Because of his writings, she also pursued her desires of being a novelist. When she heard that Masamune changed his genre, she was very upset and made plans to sabotage his romantic comedy novel to prevent him from debuting it. This was not out of malice, however, since she thought she could fire up Masamune to writing another battle manga. After learning of his and her sister's situation, she visited him in hopes to get him to work for her so she could financially support them and he'd continue writing battle manga. She even confessed to him outright, but was turned down, mirroring the same rejection Masamune was rejected by Sagiri. Muramasa has not lost heart and still supports Masamune and continues to appeal to him, both as a fan and as a girl.

Elf Yamada

Elf is Muramasa's arch-rival for Masamune's affections and generally doesn't get along with her. Because of her apathy towards others in the the light novel industry, she does not recognize Elf and continually gets her name wrong and finds her books boring. Elf, in turn, likes teasing Muramasa and causing trouble for her. However, if they both can find something to profit from each other, they are able to cooperate.

Sagiri Izumi

Muramasa's interaction with Sagiri/Ero-Manga is very little. The first time she met Sagiri was when Sagiri revealed herself on the stairway, the furthest she's been away from her room since the story began, to tell off Muramasa for trying to steal away Masamune and abandoning their dream. She also complied when she yelled at her and Elf for causing a commotion during the contest after-party. It seems that on a basic level, Muramasa respects Eromanga-Sensei, though it's unknown if she views her as another lover rival.

Ayame Kagurazaka

Despite working in the same publishing agency and being part of her editorial department, Senju doesn't recollect Kagurazaka, though Kagarurazaka assures this is because she doesn't come to the building often. However, despite not remembering her, the times she does interact with her, she takes her advice to heart, especially if it has anything to do with Masamune.

Shidou Kunimitsu

Like with everyone else, Muramasa is unfamiliar with Shidou and doesn't recognize him due to not reading his manga.


According to Elf, Senju has 7 max ranked A-Level skills, two of which are not known to her.

She has an incredibly quick writing speed, similar to Masamune.


  • She is confirmed to be one of the eight Hachiraijin, aka the "Arch-Novelists," the top best selling novelists who sold over 10 million copies.
  • Her nickname, "Kuruizaku Kuroikazuchi no Muramasa," was created by Elf, to Senju's approval.
  • Muramasa's romantic comedy short story title, "My Un-Cute Kouhai" is a nod to the author's original hit series title: "My Little Sister Can't Be This Cute."
  • Muramasa's real name is Hana Umezono, appears in Episode 10 when Izumi shares the fan letters with Muramasa.
  • Muramasa appears to be left-handed, she writes using her left hand.

Volumes and Sources

  • Oh come on, dudes, I can't do everything for this girl. Reference it yourself!
  • Well, you can say that the anime will eventually be one of the sources. Please add more to this fact.
  • Soon.
v  d  e
Main Characters Izumi MasamuneIzumi SagiriElf YamadaSenju Muramasa
Armeria AmeliaElf's MotherIzumi KotetsuIzumi KyoukaJinno MegumiKagurazaka AyameKunimitsu ShidouKusanagi RyoukiSagiri's MotherTakasago TomoeYamada Chris