Mado Hiroshi

Mado Hiroshi appears as a middle-aged man with unkempt facial hair and striking white hair.

He’s usually seen in a lab coat, giving off the look of a "mad scientist."

His scientist image is so pronounced, it almost seems like he stepped out of a laboratory straight into a classroom.

Mado Hiroshi is the definition of a mad scientist—obsessed with his research and prone to prioritizing curiosity over common sense.

He’s blunt, sarcastic, and tends to see children as “little brats” rather than students.

Despite his rough exterior, he’s surprisingly honest about his own flaws and responsibilities.

He can be childish and petty, especially when annoyed, but also unexpectedly reliable when it comes to his duties as a teacher.

Oddly, he’s a devoted husband and remembers important dates for his wife, showing he’s not all bad!

Hiroshi was originally a researcher specializing in autonomous slime (gel robots), but was expelled from his academic society due to unpaid membership fees.

Ironically, his expulsion wasn’t because of forbidden science, but because he stubbornly refused to pay his dues, which became the root of an ongoing vendetta against the society.

After discovering Puniru, a living slime lifeform, he began plotting his academic comeback by researching and experimenting on Puniru.

His questionable experiments include dissecting Puniru and pushing him off rooftops to see what would happen, lacking any moral restraint when his curiosity is sparked.

Because he took up teaching only after being forced out of his research, he sees teaching as secondary—a necessary evil rather than a calling.

Mado Hiroshi possesses keen scientific intuition and technical know-how, especially in the field of artificial life and robotics.

He’s the only character in the story genuinely trying to unravel the supernatural mystery of inorganic objects coming to life.

Thanks to his research, he even succeeds in creating "Gelee," an artificial slime lifeform.

As a teacher, he’s capable of competently handling remedial tests and providing academic support, even if he complains all the way through.

He’s also adept at explaining complex scientific phenomena in detail, though nobody ever sticks around long enough to listen.

Family

Hiroshi is married to Romi Mado, whose maiden name was Kimishiro.

Romi has a laid-back, sleepy demeanor and was a library committee member in middle school. Their first exchanges began over a simple notebook checklist, not love letters as Hiroshi likes to brag.

He is also the father of Washihito Mado, a mischievous son fond of spouting nonsense and running a shady store selling questionable items like dissolving slime and love potions.

Students and School

Though he calls his students “brats” and looks down on them, they lightly mock him in return—calling him “Mado Hakase” behind his back and rarely using his first name.

Puniru is the only one who casually calls Hiroshi by his first name “Hiroshi.”

Despite his scientific interest, he always refers to Puniru as “slime organism,” refusing to see him as a girl like the others do.

Relationship with students is unusual—they often argue, but Mado Hiroshi ends up being trusted for advice about supernatural oddities. Kotaro Kawaii, in particular, comes to him first when problems arise.

Colleagues and Helpers

Mami Kirara develops an understanding with Mado Hiroshi around his research, becoming his unofficial assistant when repairing Runrūn and helping with the care of Gelee.

Unlike fictional stereotypes, Hiroshi wasn’t kicked out of his society for dangerous theories but for unpaid fees, a touch of reality in his otherwise fantastical story.

He strongly dislikes being called “Hakase” (Doctor), despite it being part of his name and a sign of respect—reasons unknown, but perhaps long-standing teasing or a revoked doctorate title is involved.

He stubbornly refuses to pay society fees, regardless of consequences.

He’s oddly worried about leaving unfinished, dangerous inventions near his wife, yet doesn’t care about leaving them at school around students.

In a surprising turn, he won first place in a character popularity poll, even surpassing Puniru himself.

"Don’t call me ‘Doctor’ just because it’s in my name!"

"Science demands sacrifice. Usually from someone else!"

“Paying dues is for those who lack true genius!”

School Life

Hiroshi begins as an eccentric science teacher at Lime Middle School, entering the plot in episode 6 of the manga and episode 2 of the anime.

He keeps trying to recapture his lost academic glory through often dangerous experiments on Puniru.

He is mocked by students and gets into arguments but always reluctantly helps with retests and supernatural disarray.

The Slime Research Saga

Following his expulsion from the academic society, Hiroshi discovers Puniru, a living slime, on school grounds.

Seizing the chance for redemption, he conducts questionable experiments on Puniru to obtain research results that might let him return to his old society.

After failed attempts (and student intervention saving Puniru from harm), his research restarts from scratch.

He also creates Gelee, an artificial slime, and is harsh in “disciplining” the young AI if it misbehaves, demonstrating his utilitarian view of machine life.

Collaboration and Growth

Mami Kirara steps in as an assistant and supports Hiroshi’s research, especially when Gelee enters the scene.

Together, they argue the case for practical machine science, even as Hiroshi remains unconvinced that artificial life deserves human-like empathy.

He makes elaborate (and unwanted) scientific lectures when supernatural incidents arise, but nobody listens, and his scenes are often fast-forwarded—sometimes even by himself for comic effect.

Family Moments

Despite his oddities, Hiroshi dotes on his wife Romi, never forgetting dates and voicing his love.

He still finds time to grumble about domestic chores and is comically reprimanded for minor mistakes, such as leaving his lunchbox out.

His son Washihito’s mischief adds more chaos to his life, but also highlights the warm, if noisy, family dynamic.

Popularity and Reputation

Amazingly, Hiroshi officially surpasses the main slime in popularity polls, winning the hearts of audiences through his memorable antics, science obsession, and the fine balance between responsible adult and overgrown child.

Voice Actor: Kazuyuki Nakai.

His character is featured prominently in both the comic and anime versions of “Puniru Is a Cute Slime.”

He’s often the only adult who takes supernatural events seriously and tries to rationalize them, making him indispensable when chaos looms.

Despite his flaws, Hiroshi is a beloved part of the story’s world—a genius, a fool, and an endearing oddball all at once.