This guy is a pervert

"Should I put poison on his drink, Tamayo-sama?" Yushiro asked hatefully as Isao told him to prepare tea and snacks. Moreover, this bastard rudely invaded the love nest between him and Tamayo and even treated this as his place! 

Nevertheless, Yushiro only dared to say all of that when Isao wasn't around, but if Isao was around, he could only lower his head. 

"Don't." Tamayo sighed helplessly, then said, "He didn't intend to kill us immediately, and he seemed to have an interest in us. Moreover, he should have a good nose since he could find us here, so in case you try to poison him, he would kill us immediately." 

"...as expected of Tamayo-sama, your intelligence is as bright as your beauty..." Yushiro murmured, mesmerized by how amazing Tamayo was. 

"....." 

Tamayo was speechless since they were about to die, yet this guy thought about her beauty. 

"Go and prepare the tea and snacks. I will talk to him." 

"No, you can't! What if he is a beast?! What will you do if you are attacked by him!?" 

There was no way for Yushiro to let Tamayo and Isao talk alone! 

"He won't." Tamayo sighed, thinking that Yushiro was a good boy and all, but his love for her was too heavy. "Moreover, even if he attacks me, can you stop him? If my body can save the two of us, then isn't it fine?" 

"I..." 

For the first time, Yushiro was hated by how weak he was. If he was strong, then would Tamayo say all of those words to him? 

If he was strong, then would Tamayo even propose to let Isao sleep with her? 

Once again, for the first time, Yushiro hated himself. 

As for hating Isao? 

Yushiro couldn't feel a chance to run away or to kill Isao. Moreover, even if he killed Isao, then they would be attacked and targeted by the Demon Slayer Corps! 

If there was something lucky, even Yushiro could tell that Isao didn't seem to have an interest in Tamayo, and he hoped it would stay the same since, if not... he really couldn't forgive himself.

'I have to stop them!' 

Still, even if Yushiro didn't have the power to stop Isao if Isao decided to attack Tamayo, he had to be present in case something happened. Even if he died, he would protect Tamayo no matter what. 

However, what if Isao had a bad hobby by letting him watch what Isao did to Tamayo forcefully before him?

As his mind constantly struggled to decide what to do, if Isao knew what Yushiro thought, he would say that this guy was perverted. It was impossible for him to be friends with such a perverted guy, but there was no doubt that Yushiro's ability, which he gained from Yushiro's DNA, was quite interesting. 

Blindfold. 

An ability that allowed him to hide or reveal the presence of anyone with a paper-like talisman.

Tamayo was also skilled at controlling her scent, which allowed her to create illusions and various support-like effects. Moreover, her knowledge of the science and physiology of demons was amazing. 

There was no doubt that his coming to this place was the right choice, and Tamayo was the person who could return Nezuko back to a human. 

Nevertheless, as he looked around Tamayo's house and examined various records from her study and research over hundreds of years, the room was knocked lightly.

"Come in."

Hearing his words, Tamayo entered the house, but she was speechless since Isao treated this house as his, even though it was hers. Still, when she entered, she saw him clearly reading over all of her records and studies, seemingly interested in those things, which made her confused since this Demon Slayer was different from what she usually knew. 

Usually, when a Demon Slayer saw her or Yushiro, their only thought was to kill them as they were demons, yet Isao seemed to be interested in her studies, which made her think that he was different. 

"I have walked around your house, and I don't see you keeping a human." Isao turned and looked at the petite, mature woman before him. "How do you stay alive?" 

"...." 

Tamayo blinked her eyes and felt unexpected by his question, but while his question was quite rude, she answered truthfully. "We bought blood from those who were in poverty." 

"Oh, you don't kill people?" Isao asked curiously. 

"I... I have killed before, but Yushiro is different. He is a good boy, unlike me, and he has never killed anyone, so by killing me, can you let him go?" Tamayo begged as she kowtowed before Isao. 

Isao didn't say anything and looked at the entrance. "As a man, are you going to let a woman beg for your life without doing anything?" 

"If you need someone to kill, then kill me! Don't kill Tamayo-sama!" 

Yushiro quickly came out from his hiding place and stood before Tamayo. After all, she was his goddess, the person who had given him a chance to live when he was about to die. While she might be a demon, for him, she was the most perfect being, an angel sent by heaven to him before his death. 

"Yushiro, stop talking about something stupid! Just leave!" 

Yet, Tamayo only thought of Yushiro as a child, someone who should be taken care of. She had lost her family after she became a demon, losing her mind and killing everything, whether it was her husband, children, family, or all the villagers. She might be able to escape from Muzan's control, but it couldn't erase the sin that she had caused when she was a Muzan's follower. 

If someone should be killed by this powerful Demon Slayer, then it was hers! 

"Tamayo-sama, you should be the one who is leaving!" 

"Stop saying something stupid!" 

As the two argued, Isao didn't stop them and just sat quietly as he read Tamayo's records. Even though he had gotten Tamayo's memory from her DNA, reading the records gave a different feeling. 

Still, soon, they realized Isao was quiet and never said anything, which made them shut their mouths. While they didn't say anything, his silence made them choke somehow. 

"Are you done?" Isao asked. 

"..." 2x

Still, the two weren't stupid, and they knew that there must be a reason why Isao let them stay alive and didn't kill them immediately, even if he could do it. However, they didn't say anything and stayed quiet, waiting for his order. 

"You must be curious why I haven't killed you, right?" Isao smiled gently and said, "Because I saw a value in you two." 

"Value?" 2x

"I can keep you two alive, but you need to do something for me." 

"What is it?" Yushiro quickly asked, like a desperate person about to die, but Tamayo quickly scolded him for being so rude. "Yushiro!" He quickly shut her mouth, and then she looked at Isao, bowing her head. "I am sorry for his rudeness, and if you have a request to us, then please say it. I will do my best to do it." 

She didn't know what Isao wished to do, but if there was a chance that they could stay alive, then she could grasp it without hesitation. 

"Can you return a demon back into a human?" Isao asked. 

"..." 2x

Yushiro and Tamayo blinked their eyes for a while, listening to Isao's request. 

"Can you do it or not? If not, then I will erase you now." 

"I-It's possible, but I need to see the person first and... I need Muzan's blood or those demons who have received a lot of Muzan's blood," Tamayo quickly said. 

"Okay." Isao nodded. "Wait here." There was much nonsense from him, and he quickly disappeared, leaving their house immediately. 

Watching how smooth and fast Isao disappeared, the two were in a daze for a while, realizing how strong he was. 

Yushiro wanted to say that they should run away, but he could tell that if he said those words, he would be cut down, disappear, and become ash since, while Isao had disappeared, it felt like they were being watched. 

Or rather, was Isao pretending to leave and waiting for them to reveal what was hidden in their hearts? 

As Yushiro felt frightened by Isao, Tamayo became even more curious about Isao, especially when he easily agreed to her request to get Muzan's blood. 

Who was he? 

Had something huge happened between the Demon Slayer Corps and the Demon? 

She lacked a lot of information, but if Isao's existence was as strong as that Demon Slayer, who almost killed Muzan, then... her dawn would come!

No, she couldn't see the dawn, so it should be her night. 

Watching the beautiful night sky, she hoped so and decided to give her everything for Isao. 

Still, when Isao left, neither Tamayo nor Yushiro talked to each other, and they just kept quiet before they saw him return with two people; one was like a child, and the other was a mature woman. 

'Are they his little sister and mother?' 

They thought, but they also sighed in relief since they knew Isao wouldn't kill them with this.