The scenery rushed past him as Shinichi's anxiety grew.
He didn't know why Upper Moon Four had suddenly fled, but his first thought was Shinobu's safety.
This train incident was clearly part of the demons' scheme, so Shinichi couldn't rule out the possibility of other Upper Moons being involved.
If that were the case, Shinobu and Yuichiro might also encounter ambushes from Upper Moons.
Yuichiro and Muichiro's combined strength was formidable—even Shinichi would find them troublesome to deal with.
But Shinobu, with her relatively weaker combat abilities, was a different story.
Though she had trained in some assassin techniques under Lee, it hadn't significantly boosted her strength.
Reluctant as Shinichi was to admit it, he knew that among the Hashiras, Shinobu might be the weakest.
With this in mind, Shinichi pushed his speed even further.
He was already operating Forest Breathing at his limit, his blood vessels bursting under the strain of the life force surging through them.
Yet, thanks to his demon-enhanced regenerative abilities, his body held together.
Despite his powerful recovery, the ruptured blood vessels and acidified muscles subjected Shinichi to excruciating pain.
Just as Shinichi desperately rushed toward Shinobu's direction...
*****
On another front of the demon-slaying battlefield, the battle between the Demon Slayer Corps' Water Hashira Tomioka Giyu and Upper Rank Three Akaza had reached a new height.
After suffering severe injuries in his previous battle with Akaza, a humbled yet determined Giyu had undergone brutal training upon recovery.
Not only had he returned to Mt. Sagiri with Sabito to request their master Urokodaki to devise a new training regimen for him...
Upon rejoining the Demon Slayer Corps, Giyu shattered his usual aloof image.
Encouraged by his close friend Sabito, he actively sought sparring sessions and guidance from the other Hashira—particularly from the strongest among them: Stone Hashira Himejima Gyoumei and Forest Hashira Moriki Shinichi.
As senior members of the Corps, Gyoumei and Shinichi naturally didn't refuse, always willing to spar with Giyu.
However, not all Hashiras were as approachable as these two.
Sabito, the Wave Hashira, needed no mention—Giyu had lost count of their sparring sessions.
Insect Hashira Shinobu Kocho and Love Hashira Kanroji Mitsuri weren't on Giyu's consultation list—the former because she wasn't known for combat prowess among the Hashiras and the latter because Mitsuri hadn't yet been promoted to Hashira status at the time.
Sound Hashira Uzui Tengen, though flamboyant to a fault, proved remarkably reliable as a senior contemporary of Gyoumei—if one could overlook his flashy-sparkling personality.
That said, Tengen's formidable speed and raw power left a deep impression on Giyu.
Giyu even harbored a vague suspicion—that Tengen's Sound Breathing might just be an excuse.
His strength seemed less like Breathing Technique and more like an innate capability.
Flame Hashira Rengoku Kyoujurou earned Giyu's particular admiration.
Not only was Kyoujurou willing to spar with him, but his straightforward, radiant personality could thaw even Giyu's perpetually cold demeanor.
Beyond these Hashiras, the others proved less accommodating.
Maple Hashira Tokito Yuichiro would occasionally spar with Giyu.
Yet whether due to inherent Tokito family pride or other reasons, most Corps members observed that the Maple Hashira only showed warmth around the Forest Hashira—otherwise he usually maintain an aloof, rarely communicative demeanor towards others.
As for Yuichiro's younger brother, Mist Hashira Tokito Muichiro—the boy was simply an airhead, with even lower emotional intelligence than his brother.
Though likely unintentional, Muichiro's flat delivery of cutting remarks like "You're weak," "Don't hold us back," "Your sword grip resembles firewood," or "Your strength falls short of my five-year-old lumber-chopping self"—all delivered with blank expression—proved devastatingly effective.
Still, compared to what followed, the Maple and Mist Hashiras' attitudes could almost be considered cordial.
The Wind Hashira Shinazugawa Sanemi and the Serpent Hashira Obanai Iguro—towards these two, Tomioka Giyuu had always wondered if he owed them money, given how openly they displayed their hostility towards him.
Perhaps Giyu didn't know, and his dear friend Sabito couldn't bear to tell him, that his former cold and sharp-tongued personality had far surpassed even the infamous aloofness of the Maple and Mist Hashira brothers—in fact, it had been even worse...
In any case, in the eyes of the two most temperamental Hashiras—the Serpent and Wind Hashiras—Tomioka Giyuu was truly detestable.
Though his personality might have mellowed somewhat now, prejudice in people's hearts was like an immovable mountain.
There was no hope that these two would ever view him much more favorably.
Of course, despite this, they never refused Giyu's sparring requests.
But compared to matches with other Hashiras, when it came to Obanai and Sanemi, what they called "sparring" hardly fit the definition—especially when their wooden swords swung with full force towards vital points.
Obanai and Sanemi had no qualms about sending Giyu to the Butterfly Mansion for a few days.
Sanemi, in particular—Sabito, who often accompanied Giyu, was absolutely certain he had seen the man grinning viciously behind Giyu's back before their match.
With Sanemi around, Giyu never got the chance to spar with the Flower Hashira Kanae.
As Sabito put it, Sanemi was like a rooster spreading its wings to shield Kanae.
So the clever Sabito advised Giyu: if Sanemi refused a sparring match, he should simply declare his intention to spar with Kanae instead.
That way, no matter how unwilling Sanemi was, he would inevitably snatch up his wooden sword and angrily intercept Giyu before he could reach the Butterfly Mansion.
And so, under the relentless training of his fellow Hashiras, Giyu's skills improved remarkably.
Not only did his mastery of Water Breathing grow more refined, but he also glimpsed the potential to push it even further.
By studying the Breathing Techniques of other Hashiras, he might one day surpass the limits of Water Breathing and develop his own deeper sword techniques.
Even the usually stoic Giyu felt a flicker of happiness—not just at his growing strength, but at the gradual improvement in his relationships with his comrades.
"I feel like I've gotten closer to everyone. They must all see me as a friend now, right?" Giyu said to Sabito.
Sabito glanced at the frowning Serpent Hashira Obanai Iguro and the visibly furious Wind Hashira Shinazugawa Sanemi—whose grip on his wooden sword was so tight his veins bulged—and replied.
"Yeah... probably..."
*****
Giyu's strength had grown immensely, but Akaza's power remained overwhelming.
At the very least, the pressure Giyu faced now was no less than that snowy night long ago.