When Eris Boreas Greyrat left Rudeus after their reunion in the Fittoa Region, many fans believed she abandoned him.
However, the truth was completely different.
Eris realized that she had been powerless during the battle against Orsted and concluded that she could never truly protect Rudeus if she remained at her current level.
Instead of staying with him, she traveled with Ghislaine to the Holy Land of Swords, determined to become strong enough to fight alongside him as an equal.
That decision marked the beginning of one of the greatest transformations in Mushoku Tensei.
Why Did Eris Go to the Holy Land of Swords?
After witnessing the overwhelming gap between herself and Orsted, Eris understood that talent alone would never be enough.
She believed that Rudeus constantly protected her while she contributed very little in return.
Rather than remaining by his side and slowing him down, she chose to leave and devote herself entirely to becoming stronger.
She reunited with Ghislaine after returning from the Demon Continent, and together they traveled to the Holy Land of Swords.
There, Eris sought out Gal Farion, the Sword God himself, hoping to receive the most demanding training available.
Why Did Eris Train Under the Sword God?
The Sword God Style perfectly suited Eris’ personality.
She naturally fought with aggression, confidence, and fearless determination.
Unlike many students who struggled to adapt to the style, Eris already possessed the mindset it demanded.
Instead of changing who she was, Gal Farion refined her natural instincts.
He transformed her reckless aggression into disciplined offense while preserving the fierce determination that made her dangerous.
Because her personality aligned so well with the philosophy of the Sword God Style, her growth accelerated far beyond that of most other disciples.
What Kind of Training Did Eris Go Through?
The Holy Land of Swords was home to the world’s strongest practitioners of the Sword God Style.
Training there was far more brutal than ordinary sword practice.
Every day, Eris fought opponents stronger than herself, suffered repeated defeats, and learned through real combat.
Every mistake was punished immediately, forcing her to sharpen her instincts, improve her reaction speed, and refine her technique.
Gal Farion did not simply teach sword techniques.
He pushed his students to develop the speed, aggression, and decisive execution required to defeat an opponent before they could even react.
Through years of relentless training, Eris gradually transformed from a talented swordswoman into an elite warrior.
Why Did Eris Lose to Isolde Cluel?
Despite becoming stronger, Eris still possessed a major weakness.
During her battles against Isolde Cluel, a skilled practitioner of the Water God Style, she suffered repeated defeats.
The problem was not Eris’ strength but her fighting habits.
She constantly released intense bloodlust before attacking, making her intentions obvious.
Because the Water God Style specialized in defense, observation, and perfectly timed counterattacks, Isolde easily read Eris’ killing intent, predicted her movements, blocked her attacks, and exploited every opening.
Although Eris possessed overwhelming offensive power, her predictability allowed Isolde to counter her repeatedly.
In a real battle, Eris would have been defeated almost instantly.
How Did Eris Overcome Her Weakness?
Rather than accepting defeat, Eris continued to improve.
She realized that constantly displaying bloodlust only gave experienced opponents valuable information.
As a result, she learned to suppress and control her killing intent instead of revealing it before every attack.
She also refined her timing, varied her attack patterns, and became far less predictable.
Combined with her ever-increasing speed and combat experience, these improvements allowed her to bypass the defensive techniques that had previously stopped her.
Instead of relying purely on aggression, Eris learned when to conceal her intentions and when to unleash them.
This made her a much more complete swordswoman.
Why Did Gal Farion Invite Auber Corvette to Train Eris?
As time passed, Gal noticed that her growth started to slow down.
Eris had become extremely powerful in direct combat, but her fighting style remained too straightforward.
She relied heavily on speed, strength, and instinct, which made her predictable against more experienced and unconventional opponents.
To solve this problem, Gal brought in Auber Corvette, also known as the Peacock Sword.
Auber was a North Emperor who specialized in the North God Style, and his approach to combat was completely different from Eris’ training under Gal.
He did not fight like a traditional swordsman.
Instead, he fought like an assassin.
Auber used ambushes, hidden weapons, traps, deception, and unconventional tactics to defeat his opponents.
This made him the perfect teacher for Eris because he targeted the exact weakness she had struggled with: predictability.
Rather than teaching Eris through ordinary sword lessons, Auber fought her as if he were genuinely trying to kill her.
This forced Eris to deal with attacks that she could not simply overpower with speed or strength.
She had to learn how to read her surroundings, anticipate unexpected attacks, and think several steps ahead.
The training also taught her that winning a fight did not always mean defeating an opponent in a straightforward duel.
Sometimes, the strongest attack was the one the enemy never saw coming.
This was especially important for Eris because the Sword God Style focused heavily on overwhelming an opponent with speed and power.
Auber showed her how those strengths could become weaknesses if an enemy refused to fight on her terms.
How Did Auber Corvette Help Eris Become Stronger?
Through this training, Eris became much more adaptable.
She learned to combine the explosive offense of the Sword God Style with the unpredictable tactics of the North God Style.
This did not mean that she completely abandoned the Sword God Style.
Instead, she added another layer to her fighting ability.
She could still overwhelm an opponent with incredible speed, but she could also deceive them, change her approach, and respond to situations that could not be solved through brute force alone.
Her mental growth was just as important as her physical improvement.
Eris became calmer and more analytical during combat.
She no longer relied entirely on her instincts or charged directly at every opponent.
She learned to observe, adapt, and look for opportunities before committing to an attack.
This training helped Eris overcome one of the biggest limitations of her earlier fighting style.
She was no longer simply a powerful Sword God Style fighter.
She became a much more unpredictable and complete warrior.
Auber’s training therefore played a crucial role in Eris’ development.
How Much Stronger Did Eris Become?
Eris’ training accomplished far more than simply increasing her physical strength.
It transformed every aspect of her combat ability.
Her reaction speed became significantly faster, her techniques became far more refined, and her instincts evolved through countless life-and-death battles.
Most importantly, she overcame the flaws that had once limited her.
By eliminating her predictability and combining overwhelming speed with disciplined technique, she reached a level where she could defeat opponents who had previously countered her with ease.
Although she officially became a Sword King, many fans considered her combat ability to be comparable to that of a Sword Emperor.
Gal Farion himself recognized her extraordinary talent and believed she had reached the point where he had little left to teach her.
Final Thoughts
Eris’ journey proved that true strength did not come from talent alone.
Although she already possessed exceptional natural ability, she only reached her full potential after recognizing her weaknesses and relentlessly working to overcome them.
By the end of her training, Eris was no longer the reckless girl who relied solely on instinct and courage.
She became a disciplined master of the Sword God Style whose speed, precision, and adaptability placed her among the strongest swordsmen in the world.
Gal Farion had refined her natural talent and turned her into a formidable swordswoman.
Auber then taught her how to use that power in ways her opponents could not easily predict.
Together, the two forms of training transformed Eris from a straightforward powerhouse into a dangerous and adaptable swordswoman.
Her transformation from an impulsive noble girl into a Sword King was one of the greatest character developments in Mushoku Tensei.
