Yasushi

Yasushi is depicted as having messy hair and an unkempt beard, giving him a disheveled and lazy look. He dresses somewhat like an old-fashioned Japanese ronin.

Yasushi is fundamentally a slacker motivated by self-preservation.

He borders on petty criminality due to his sticky fingers but stops short of outright evil because of a minimal sense of conscience.

He is skilled at bluffing and maintaining composure, even before supernatural threats.

Despite his unserious demeanor, Yasushi avoids trouble when possible and often manipulates situations for his own safety.

Originally a traveling trickster and street performer, Yasushi never stuck with any martial art for long, only learning their basics.

He becomes the "master" of the Issen School, a fighting style largely based on parlor tricks, purely by chance.

Before Liam Sera Banfield inherited his title, the Banfield family had a dreadful reputation, leaving them unable to hire decent martial artists.

Yasushi is sent to the Banfield family as a last resort, in exchange for settling another man's debt.

As a swordsman, Yasushi is pitifully weak—barely better than a normal civilian.

However, he accidentally invents absurd training tasks and sleight-of-hand "techniques" that his disciples execute with terrifying success.

He becomes renowned as a sword instructor, as his students—Liam and others—grow to monstrous strength under his lazy tutelage.

Liam Sera Banfield

Yasushi serves as Liam's master, initially pitying the earnest young noble forced to study under him.

He bluffs his way as a grandmaster, but Liam takes each of his schemes seriously and excels beyond expectations.

This unnerves Yasushi and eventually leads him to flee the territory.

Nina

Yasushi's wife, Nina, is obsessively attached to him—she is both highly competent and a classic "yandere."

Instead of leaving her useless husband, she literally stabs him to keep him from escaping.

She later persuades him to open the "Original Issen School Dojo" and sticks with him even during his flight to the frontier.

Yasuyuki

Yasushi and Nina's son, Yasuyuki, grows up surprisingly upright and promising, despite his dubious parentage.

Though Yasushi jokingly claims his son is talentless, Yasuyuki impresses even the staunchest knights with his balanced skills.

Amagi, Brian Beaumont, and Others

Characters like Amagi, Brian Beaumont, and others are deeply suspicious of Yasushi, doubting his abilities and credibility.

However, because Liam trusts Yasushi and shows immense growth under his guidance, no one dares to oust him.

Liam’s direct disciple Ellen and the mysterious Ciel also find Yasushi’s shady and uninspiring aura unsettling.

Arrival at the Banfield Territory

Yasushi is introduced to the Banfield family as their sword instructor, having been sent in place of an indebted man.

He initially plans to pass time and scam money with cheap tricks, showing off the "Issen" technique, a flashy parlor trick.

Transition to Accidental Greatness

Much to Yasushi's horror, Liam successfully performs every farfetched training or "move" he sets, far surpassing his expectations.

Liam’s rapid growth, alongside his own unfounded reputation as a mysterious master, causes Yasushi considerable anxiety.

The Great Escape

As Liam continues to grow stronger and purges the territory of corrupt officials, Yasushi begins to fear for his safety.

He cleverly buys time by assigning Liam complex repairs to the mobile knight Avide, intending to keep Liam occupied and spend his funds.

Once he senses he cannot teach Liam anything further, Yasushi hastily grants him the highest certificate of the Issen School and disappears.

Fostering Assassins

On the run, Yasushi discovers that his reputation as Liam’s master puts his life in danger everywhere he goes.

Guided by The Guide, he raises orphans Fuuka and Rinhou as assassins to eliminate Liam.

However, hedging his own bets, he tells them to obey Liam as their senior if they lose.

Both orphans are defeated and join Liam, inadvertently increasing Liam’s strength—and angering The Guide.

Antagonist Again and “Original Issen School”

Encouraged by Nina, Yasushi takes on the name Anjirou and attempts a comeback as the founder of the “Original Issen School.”

His students there are summarily crushed in battle against Liam and his allies.

Yasushi fakes his death to escape yet again, now sporting a large chest wound—inflicted by his own wife.

Ongoing Legacy

Despite being a hopeless fraud, Yasushi repeatedly finds himself at the center of history, his fabricated techniques propelling his students to legendary status.

His legacy lives on even as he tries—unsuccessfully—to keep out of the limelight.

Yasushi is one of the few major named characters in the series who is a commoner, not a noble.

He has no strong feelings against AI, only a rough awareness that nobles dislike them.

His line of work and flamboyant skills arose from his background as a street performer.

"I only taught the basics, but they turned into monsters."

"If you lose, just listen to your senior disciple, okay?"

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