Sumire Kageishi

Sumire Kageishi is a female teacher and homeroom advisor at the high school attended by Akiteru Ōboshi, Iroha Kohinata, Ozuma Kohinata, and Mashiro Tsukinomori.

She is known among students for her harsh discipline, fierce attitude, and cutting remarks, earning her the nickname “Queen of Deadly Poison.”

Despite this intimidating public persona, her real personality is surprisingly sloppy and lazy in her personal life.

She is incapable of handling basic household chores such as cooking and cleaning and tends to let everything around her fall into chaos.

Sumire has a heavy attraction to younger boys, specifically boys aged 15 and under, and enjoys boys’ love (BL) as a hobby.

She is also an otaku creator who produces works in these genres and participates in events and conventions.

Under the pen name Lady Murasaki, she works as an illustrator, especially for BL and similar genres.

It is through this side job that she gets drawn into the Fifth-Floor Alliance led by Akiteru.

Sumire serves as a teacher and homeroom advisor for the class that includes Akiteru Ōboshi, Iroha Kohinata, Ozuma Kohinata, and Mashiro Tsukinomori.

Within the school, she maintains a strict, high-pressure style of guidance.

Her way of speaking is sharp, brutally honest, and often laced with “verbal poison.”

Because of this, many students are afraid of her and try to avoid getting on her bad side.

The nickname “Queen of Deadly Poison” reflects how merciless she can be in class, from strict grading to harsh critiques of student behavior.

However, this is largely a façade she maintains as her “public face” as a professional teacher.

Despite being feared, she is not incompetent at her job; she simply separates her teacher persona from her private life.

Her students rarely suspect how chaotic and dependent she actually is outside of work.

In her private life, Sumire is extremely irresponsible with daily life tasks.

She cannot cook, clean, or manage basic housework, and her living environment tends to become messy quickly.

Her sloppy nature extends to her work as an illustrator, where she frequently fails to manage her schedule.

She often misses deadlines and has trouble keeping up with commitments, frustrating those who rely on her.

Because she cannot handle everyday tasks, she inadvertently burdens people around her, especially Akiteru and the other members of the Fifth-Floor Alliance.

They are frequently exasperated by her lack of self-management and the trouble that follows.

Her otaku hobbies center on younger boys and BL pairings, which she treats both as entertainment and as inspiration for her creative works.

This combination of strict teacher and messy otaku makes her a highly contradictory and comedic character.

When acting as an illustrator, Sumire uses the pen name Lady Murasaki.

In this creator persona, she is part of the Fifth-Floor Alliance and works closely with Akiteru Ōboshi.

Her illustration skills are high enough that Akiteru personally took an interest in her work.

Artistically, she is talented and expressive, especially in romantic and emotional scenes.

Sumire was discovered when she was participating in an event, carrying the self-published BL and younger-boy-themed doujinshi she had created.

Akiteru, who was searching for an illustrator for his own projects, encountered her there.

This chance meeting led to Akiteru discovering her secret hobbies and pen name.

Because he essentially gained leverage over her by knowing this side of her, she ended up being pulled into the Fifth-Floor Alliance as a member.

When she switches into her Lady Murasaki mode and is with the Fifth-Floor Alliance, her behavior becomes very different from her school persona.

She shows anxiety about deadlines, panics about her situation, and is much more submissive and frantic.

Akiteru Ōboshi is technically her subordinate in terms of school hierarchy, since Sumire is a teacher and he is a student.

However, within the Fifth-Floor Alliance and their creative projects, the power balance flips in a strange way.

Sumire addresses Akiteru as “Akiteru-sama”, treating him with exaggerated respect and flattery.

She often grovels, begs for forgiveness, and even goes as far as kneeling in apology when she fails to meet expectations.

Her repeated schedule failures, missed deadlines, and irresponsible decisions constantly earn her lectures from Akiteru.

He scolds her harshly and even resorts to comical “pressure point” punishment when she crosses the line.

During the marriage proposal incident arranged by her family, she dragged the entire Fifth-Floor Alliance into the chaos.

This pushed everyone’s patience to the limit and made her fear for her career and social standing.

Because Akiteru knows both her respectable teacher side and her chaotic otaku side, he holds enormous influence over her.

In turn, she is dependent on him to handle the fallout of the problems she creates.

Sumire is a full member of the Fifth-Floor Alliance, a group that includes Akiteru Ōboshi, Iroha Kohinata, Ozuma Kohinata, and Mashiro Tsukinomori.

Her role centers on illustration work and creative contributions to their projects.

She was not originally planning to join the group, but became involved after Akiteru discovered her secret activities as Lady Murasaki.

Feeling cornered by the possibility that her hobbies and doujin work might be exposed, she reluctantly agreed to cooperate.

Among the alliance members, she is seen as a troublesome but necessary talent.

Her art quality is recognized and valued, but her inability to manage time and responsibilities makes her a constant source of crises.

Her presence brings comedic chaos to the alliance, as she frequently causes trouble that the others need to clean up.

Still, she remains an important member because her illustrations significantly boost the appeal of their projects.

Sumire often overextends herself by accepting responsibilities she cannot realistically handle.

One major example is when she casually agreed to take on the role of advisor to a sports club.

The extra burden from the sports club clashed with her already unstable illustration schedule.

To escape this situation, she begged Akiteru and the others to help her shift the school’s attention toward the drama club.

Her desperation was partly because her younger sister, Midori Kageishi, was the head of the drama club.

She wanted to strengthen that club instead, using it as an excuse to avoid the responsibilities she had rashly accepted.

In another case, a marriage proposal was arranged by her family, which turned into a major incident.

She pulled the members of the Fifth-Floor Alliance into the drama, causing large-scale trouble for everyone.

During this marriage proposal fiasco, Ozuma Kohinata went so far as to threaten to report her to the Board of Education.

He implied he would expose her secret life and inappropriate hobbies, effectively destroying her career.

Realizing that her personal and professional life were at risk, Sumire broke down in tears.

She cried that she would be “socially dead” if everything came to light, highlighting how fragile her position truly is.

Publicly, Sumire appears strict, cold, and unyielding.

She embodies the image of a fearsome teacher who does not tolerate laziness or carelessness in her students.

Privately, she is disorganized, easily flustered, and extremely indulgent in her own hobbies.

Her lifestyle is dominated by otaku interests and procrastination rather than discipline.

She has a strong preference for boys aged 15 and under and enjoys BL-oriented media and creations.

While this is a significant part of her personality in the narrative, it is also a source of comedic danger for her career.

Her fear of being exposed creates a constant tension between her teacher persona and her Lady Murasaki persona.

This duality makes her an entertaining character who is always one step away from catastrophe.

At the same time, her genuine artistic talent and occasional moments of sincerity keep her from being purely a joke character.

She is flawed, chaotic, and often selfish, but also hardworking in short bursts and deeply invested in the creative projects she joins.