"Huft... Huft... Huft..."
Unknowingly, within the unfinished training ground, the myriad flashes of blades and booming echoes had vanished without a trace, leaving only the sound of rapid breaths reverberating through the air.
A group of Hashira, who could maintain a steady breath even in their sleep and had honed their breathing style to the extreme, found themselves unable to control their quickening breaths at this moment.
"Two hours?"
Riezel estimated the time and realized that the Hashira had been fighting fiercely for a full two hours without any breaks in between.
Amid such intense combat, continuously fighting for two hours straight, it was no wonder even these Hashira, who had mastered their breathing style to the extreme, couldn't help but need to take a breather.
Especially Kyoujurou and Sanemi, who were now lying on the ground, unable to get up.
Seeing this, Riezel finally called a halt.
"Let's call it quits here." Riezel declared to everyone. "It seems my guess was correct; awakening the Mark from scratch isn't easy."
"What should we do next?" Tengen, sweating profusely, pushed back his hair. "We followed your instructions and put on a flashy performance, but still couldn't awaken the Mark. Will all our efforts end up being in vain?"
"It won't... huft... for sure!" Kyoujurou, still catching his breath, exclaimed loudly. "Even if we couldn't awaken it, training like this will surely have its meaning!"
"After fighting for so long, I'm starving..." Mitsuri said tearfully, her hands hanging limply by her sides, clearly exhausted.
"Hold on a little longer. Lunchtime will be here soon." Obanai said softly to her.
"Hmph."
Seemingly unwilling to accept defeat, Sanemi snorted and tightened his grip on his sword before turning to Gyoumei.
"Himejima, I'll spar with you next."
"Amitabha."
Gyoumei, perhaps the one in the best condition among the Hashira, appeared not to have broken a sweat.
"Wind Hashira is right." Gyoumei nodded. "If one attempt fails, we must continue. We can't give up just because of one failed attempt."
"Yeah..." Shinobu chuckled bitterly, brushing the dust off her clothes. "Even though it might not be rehabilitation training since my injuries have already healed, it's still better to keep my body moving. I don't want to get beaten so badly by an Upper Rank again."
"...Me neither." Muichirou said faintly. "I don't want Master to face danger again while I'm powerless to help."
Eventually, all the Hashira voiced their determination, lifting the spirits that had been somewhat low.
"Well, it's my turn next..."
On the side, Giyuu seemed to seize the moment, preparing to form a group.
Unfortunately—
"Mitsuri, how about we spar next?"
Shinobu extended an invitation to Mitsuri.
"Um, sure! I'm down for it!" Mitsuri readily agreed.
As the only two females among the Hashira, the relationship between Shinobu and Mitsuri was quite solid. Sometimes, Shinobu would even seek Mitsuri's advice on cooking, so they could be considered close friends.
"Uzui, let's have a match."
Obanai also invited Tengen.
"Sure thing! Though snakes aren't exactly flamboyant, your eyes are! Let's have a splendid showdown!"
Tengen, intrigued by Obanai's invitation, promptly accepted.
Even though Tengen, who had a penchant for flamboyant things, wasn't too fond of Obanai's gloomy personality, Obanai's heterochromatic eyes seemed to pique his interest.
"Now, it's just us left, Young Tokitou. Show me what you've got!"
Kyoujurou flashed a cheerful expression at Muichirou.
"Okay."
Muichirou seemed to have a favorable impression of Kyoujurou, as his expression visibly softened.
And thus, the Hashira successfully formed groups once again, except for one.
"..."
Giyuu was once again left alone.
However, just as the Hashira were preparing to engage in another round of battles, suddenly, the situation took a turn.
An astonishing imposing pressure emanated from Riezel's body, causing the faces of the Hashira to change drastically.
"Young Tsugikuni?"
"Tsugikuni?"
Kyoujurou and Shinobu were stunned in succession.
"What the—Oy!"
"Whoa, wh-what happened?!"
Sanemi couldn't help but call out to Riezel, while Mitsuri exclaimed in panic.
At this moment, all the Hashira also showed varying degrees of astonishment, their eyes filled with disbelief as they looked at Riezel.
Riezel had closed his eyes at some point, emitting an astonishingly high temperature from his body, causing both his body temperature and breathing rhythm to change.
"Huhh... Hahh..."
Riezel adjusted his breathing, his chest rising and falling like a bellows.
In this situation, the Hashira could clearly hear his heartbeat.
*Ba-dump!* *Ba-dump!* *Ba-dump!*
As his heartbeat intensified and quickened, coupled with Riezel's rising body temperature, a dark pattern gradually emerged on his forehead.
Yes.
Riezel had awakened the Demon Slayer Mark.
Every Hashira who witnessed this scene was incredibly shocked and bewildered.
It wasn't until Riezel calmed his breath that he opened his eyes and looked at his hands.
"So, this is the Demon Slayer Mark, huh?" Riezel muttered to himself. "It's indeed an interesting ability."
Upon hearing his mutter, all the Hashira finally snapped out of their shock and bewilderment.
"Oy, Oy! What are you doing?!" Tengen asked in disbelief. "Are you trying to get yourself killed?!"
Previously, Riezel had explicitly stated that he didn't want to awaken the Demon Slayer Mark due to its side effect. Yet here he was, having suddenly awakened it, unleashing this deadly ability that could shorten one's lifespan to less than 25 years.
For this reason, it was understandable for Tengen to feel disbelief. Even the other Hashira were perplexed and unavoidably moved by Riezel's actions. Especially Kyoujurou and Shinobu, who had a relatively good relationship with Riezel, displayed some urgency on their faces.
"Young Tsugikuni!" Kyoujurou shouted loudly.
"Tsugikuni..." Shinobu looked at Riezel with a complex expression.
Riezel lowered his hands, raised his head, and looked at the Hashira before him, whose expressions ranged from astonishment to incomprehension to disbelief, with an exceptionally calm expression.
"It can now be confirmed that the first person to awaken the Mark should preferably be users of Sun Breathing." Riezel explained calmly to everyone. "At least, Sun Breathing users are relatively more likely to awaken it when there are no Marked Demon Slayers around."
Just now, Riezel used the evolved Sun Breathing to raise his body temperature to 39 degrees Celsius and adjust his heartbeat, increasing the frequency to over 200 beats per minute, which resulted in the direct awakening of the Demon Slayer Mark.
This was enough to prove that the first person to awaken the Demon Slayer Mark would most likely be users of Sun Breathing—or perhaps only Sun Breathing's users could be the first ones to awaken it.
In the original work, Yoriichi was born with the Demon Slayer Mark. After joining the Demon Slayer Corps, he stimulated other Demon Slayers, causing them to awaken it one after another.
However, when Yoriichi left the Corps and Demon Slayers with the Demon Slayer Mark died out, there were no more instances of its awakening among them.
Moreover, the current Hashira also only awakened the Demon Slayer Mark after Tanjirou did so in the original work. Before that, regardless of how intense their battles with demons were, even to the point of sacrificing their lives, there was no sign of them awakening it.
The prime example of this was Kyoujurou, who died at the hands of Akaza during the Mugen Train Arc.
Clearly, the intense battle between these two lasted from night until dawn and from dawn until the sun rose. Kyoujurou fought fiercely until the end, even risking his life to drag Akaza until daylight.
Despite such an intense battle, was it possible for Kyoujurou's body to still not have a temperature of 39 degrees or an increased heartbeat of over 200 beats per minute?
Impossible.
Kyoujurou, a user of Flame Breathing, often raised his body temperature during battles. It was also not uncommon for his heartbeat to intensify due to his breathing style, which strengthened his heart and lungs and accelerated blood flow.
However, despite all of this, Kyoujurou still hadn't awakened the Demon Slayer Mark.
Meanwhile, it was the other Hashira who awakened the Demon Slayer Mark effortlessly after Tanjiro's awakening.
As Riezel thought about this and saw that the Hashira still couldn't awaken the Demon Slayer Mark with the method mentioned in the original work, he began to suspect.
"If users of Sun Breathing don't awaken the Mark first to trigger the awakening of those around them, then perhaps none of you will be able to successfully awaken it no matter how hard you try."
Riezel explained to the gathered Hashira while touching his forehead where the Demon Slayer Mark was.
"Now, you can try again and see if you can awaken it."
Upon hearing this, the Hashira fell silent one after another.
Even Sanemi and Iguro stared at Riezel with complex emotions in their eyes.
Seeing this, Riezel spoke up to correct any misunderstandings.
"Don't misunderstand. I'm not opening this lifespan-reducing ability for your sake, okay?" Riezel said calmly. "I have a way to remove it, so you don't need to worry."
As soon as he finished speaking, all the Hashira were stunned.
"Is that true, Young Tsugikuni?" Kyoujurou quickly asked.
"It's true." Riezel nodded.
He wasn't lying.
It was worth noting that his decomposition magic was an imaginary system capable of decomposing not only physical things but also immaterial things, such as magic itself.
If that were the case, such magic should be feasible for decomposing the Demon Slayer Mark, right?
Even if it couldn't, it really wouldn't matter.
After all, dimensional travel only brought his consciousness, so even if he died, it was just the end of the dimensional travel, without harming his original body. As long as he didn't awaken the Demon Slayer Mark on the Akasha Continent with his real body, it shouldn't have affected his lifespan.
Based on this consideration, Riezel chose to awaken the Demon Slayer Mark in front of the Hashira without hesitation.
With him awakening the Demon Slayer Mark, the Hashira should be able to awaken it quickly, right?
As it turned out, Riezel's assumption was correct.
After he awakened the Demon Slayer Mark, as the Hashira managed to raise their body temperatures to 39 degrees and increase their heart rates to over 200 beats per minute, they consecutively awakened their own Demon Slayer Marks.
"We did it!"
Sanemi clenched his fists and exclaimed in excitement as a green windmill pattern appeared on his right cheek.
"It's a success indeed..."
Obanai looked at his left hand, where a purple snake-like pattern extended up to his left cheek.
"Is this the Demon Slayer Mark?"
Muichirou touched his face, where a cloud-like pattern stretched from his left temple to his right cheek.