After bidding farewell to Mitsuri and Obanai, Hiru headed straight for the training grounds with Muichiro.
On the grounds, Rengoku Shinjuro and Rengoku Kyojuro were supervising the swordsmen's training. Or rather, Shinjuro was giving orders, while Kyojuro was training alongside the swordsmen.
Since the injured Kyojuro was training together with them, the already exhausted swordsmen didn't dare to rest. They all followed behind him in a daze.
To make matters worse, Kyojuro was full of energy as he encouraged them.
"You're all really full of spirit! Let's do three more rounds then! To face the demons, we all need to train hard!"
The swordsmen: …!!!
Hiru could clearly see their already near-collapse expressions grow even more desperate. But at that moment, Shinjuro's voice rang out across the entire field.
"Everyone, rest where you are!"
Hiru withdrew his gaze from the field and turned to look at Shinjuro, who was walking over with a stern face. He raised a hand in greeting, then stood by the doorway waiting for the two of them.
Shinjuro's already fierce features looked even more unapproachable. He strode up to Hiru, his voice low.
"We need to talk."
Hiru gave a small shrug.
"Actually, it's pretty obvious. I don't have anything to explain."
"You. "
"Hiru-dono!"
Kyojuro hurried over as well.
"I received a letter from Oyakata-sama! You've really killed another Upper Moon?"
Hiru nodded slightly.
"I just helped clean up at the end."
"That's truly inspiring!"
Hiru glanced at the swordsmen in the arena, all of them straining to listen, then at the veins bulging on Shinjuro's face. He sighed.
"…Let's go. We'll talk somewhere else."
Even after moving indoors, Shinjuro only glared fiercely at Hiru. In the end, he said nothing. He stood up in irritation, slammed the door, and left, venting his frustration on the training squad.
He had no reason to be angry.
To turn his blade against someone who had shown him so much kindness simply because of a change in status.
He couldn't do that.
But how could he remain indifferent?
His position dictated that he could not, and should not, remain indifferent.
"Damn it!"
Shinjuro's roar startled all the swordsmen under his instruction.
Compared to the relatively easygoing Kyojuro, the swordsmen didn't dare complain at all in front of Shinjuro. And now, faced with an obviously enraged Shinjuro, they tensed their entire bodies and focused on training, not daring to make a sound.
After Shinjuro left, the atmosphere in the room visibly relaxed.
Hiru looked at the paper sliding door that had been torn off, then shrugged at Muichiro and Kyojuro.
"Well, looks like he'll need some time to accept it."
"Mmm! Father actually holds Hiru-dono and Yoriichi-dono in very high regard! That's exactly why he finds it so hard to accept the current situation!"
Kyojuro remained as energetic as ever.
"But it's not just Father! Even I, who found out first, still can't sleep well because of this! No matter how many times I think about it, it still feels unbelievable!"
"Yeah, I should've used Blood Demon Art back then instead of just making something up…" Hiru sighed.
"You got Oyakata-sama's letter, right?"
"Yes! Oyakata-sama said Hiru-dono will be staying at our home for a while, until Tanjiro returns to being human! Please feel free to stay! I'll try to persuade Father again!"
"There's no need… By the time he comes around, I'll probably be in the ground already."
Hiru waved his hand.
"I'm going to see Tamayo. Do you want to come with me?"
"Mmm, I've already visited her. The Kamado boy is doing very well! Should we send a letter to his family? After all, returning to being human is a major matter!"
Hiru paused for a moment before replying.
"Hmm… we should ask what he wants first. By the way, you're not coming, right?"
"Mmm! Hiru-dono probably has something to discuss privately, right? It wouldn't be convenient if I came along. Just pass on my greetings to Miss Tamayo and Yushiro!"
Kyojuro smiled brightly.
"But if you plan to go anywhere afterward, please be sure to let me know!"
"If you're going to write a report, then you should just come along yourself…"
Hiru sighed.
"I don't have anything to hide."
"No! This isn't about hiding anything. There are some situations where, because of my position, it's simply not appropriate for me to be present.
Even if I personally agree, that won't change it!"
Kyojuro watched as Hiru and Muichiro stood up, his voice still loud and cheerful.
"But if Hiru-dono is willing to tell me afterward, I would be very happy to listen!"
"Haha…"
Hiru laughed, but couldn't help shaking his head.
"You Rengoku family really are my natural nemesis… Come on, Muichiro. I'll take you to meet the genius apothecary I mentioned."
"Can she solve my Slayer Mark problem?"
Muichiro politely said goodbye to Kyojuro and followed after Hiru.
"Even Hiru-nii couldn't do anything about it."
Hiru reached out and ruffled Muichiro's hair.
"Hmm… aside from her, I really can't think of anyone else who might be able to help."
"What kind of person is that apothecary?"
"Her…"
Hiru truly trusted Tamayo's pharmaceutical skills. Even after being subtly stabbed by his own child just moments ago, he still didn't hesitate to praise Tamayo to him. Though Tamayo herself wished Hiru wouldn't place so much faith in her.
"A medicine that can counteract the side effects of the Slayer Mark?"
"Yes. I hope you can take some time to research it."
Tamayo looked at Muichiro chatting happily with Tanjiro and couldn't help taking a deep breath.
"Hiru-san.
I must emphasize this again. My abilities are not as exceptional as you believe. If it is poisoning or a malignant illness, you may entrust it to me without concern. Research related to demons is also barely manageable. But.
If the Slayer Mark is as you described, then it has clearly exceeded the scope of my research. Moreover, humans are different from demons. If such symptoms appeared in demons, I could repeatedly conduct experiments on them. But for humans, simply finding suitable test subjects is already an insurmountable obstacle."
Hiru felt he was putting her in a difficult position, so he cleared his throat and looked away.
"Let's set that aside for now… How is Tanjiro's medicine progressing?"
Tamayo frowned slightly. After a brief silence, she spoke again.
"I am currently cultivating the most troublesome yet indispensable strain. It will likely take about a week more. Everything else is already prepared. Once the strain matures, I can immediately formulate the medicine and administer it."