Animeverse Slayer!

Leo and Shinobu were seated next to each other, both of them stared intently at the woman before them.

"Please, have some tea first."

Leo didn't stand on ceremony and picked up the cup of tea and sipped it, Shinobu also did the same. They weren't afraid that she would poison them, with Shinobu here no poison could harm them.

The boy next to the lady was nervous and kept glaring at Leo and Shinobu.

After finishing the cup Leo placed it back and asked lightly, "Lady Tamayo, What are you?"

Tamayo was confused.

"I am a demon, of course."

Leo shook his head and said, "That's not what I am asking. You are a demon but what I have seen in every demon is missing from you."

"And what is that?"

"Malice."

Like Leo said before, this woman named Tamayo and that boy Yushiro had no malice. Any demon entertaining the thought of eating human flesh will have malice or other equally disgusting vibe to their spirit. However these two didn't.

Though one of them has killed humans before, the kind of emotion within her was sorrow, despair and rage. That last emotion was especially strong, it was like a bright flame burning fiercely within the darkness.

The lady didn't show any change to his words and said, "I don't know about what you meant but I have never harmed humans, atleast not while I was sane."

"What does that mean? You killed humans when you weren't sane?"

Shinobu couldn't help but voice out her words.

"Shut your mouth! Lady Tamayo has never killed any humans on her on will, it was that bastard Muzan! If it weren't for him...

"That's enough, Yushiro."

"I am sorry, Lady Tamayo."

Yushiro who was flaring up against Shinobu bowed and apologized before backing away. However he kept glaring at them.

"Please forgive him for his rudeness."

"It's alright. But you have to explain what you are."

Leo said lightly. Tamayo nodded.

"I am more three hundred years old. During my days as a human I was terminally ill and couldn't even move. My husband and my son were deeply worried for me. Many doctors have tried and countless folk medicines were used and yet I wasn't cured."

"It was at that time Muzan visited me. He offered me my life back, under tremendous joy I agreed but never did I imagine that day to be the nightmare that would haunt me to this day."

"All I wanted was to grow old with my husband, to watch my son grow up, to hold my grandchild. But that man destroyed everything. He cured my body by turning me into a demon. The moment of transformation clouded my mind."

"In my moment of insanity I killed my husband and my son. When I woke up everything was gone, the man I vowed to the heavens to spend my days with, my child I promised to protect and watch over... everything was gone."

Leo felt a pang in his heart. Wasn't he the same, living with the pain of losing everyone he had ever cared for.

"I am sorry."

Tamayo shook her head, her face still had that indifferent look but deep down Leo could see her sorrow.

"Muzan is a monster, in his eyes human lives have no value. During the time he controlled me I have seen him kill hundreds of innocent people."

"Then how did you escape?"

Shinobu asked.

"It was roughly three hundred years ago, Muzan and I met a Slayer in a bamboo forest. He was different from all the others before him, his eyes had the look of a primal beast rather than a human being."

"Without even a moment of hesitation that man attacked Muzan. Their battle destroyed the bamboo forest, laying everything to waste. Not even one of Muzan's attacks scratched that Slayer, he was utterly crushed."

"Knowing his end was near Muzan split himself into hundreds of pieces of flesh and scattered away. That Slayer was able to cut down more than a thousand but unfortunately Muzan still escaped. "

"That was the only point in a thousand years where Muzan was at his weakest, his control over me diminished, allowing me to escape."

Leo and Shinobu drew in a cold breath. Muzan was almost killed three hundred years ago! He was just a breath away from death.

"Who was that Slayer?"

"Yoriichi Tsugikuni."

Leo looked at Shinobu and the latter shook her head.

"I have never heard of his name."

"That's strange, if a person like him who nearly killed Muzan appeared within the Corps he shouldn't be a nobody."

"Um, I will try the archives and try to find something."

Tamayo waited for them to finish their conversation before asking.

"What do you plan to do with us?"

Hearing her Leo and Shinobu hesitated.

"Demon Slayers duty is to kill demons however, we aren't mindless idiots. We know when to raise our sword and when to put it down."

"Thank you."

Tamayo bowed her head and said sincerely. Leo sighed and said.

"I know what it feels like to lose someone but to have lived so long bearing such a heavy heart, I can't imagine what it is like."

Tamayo raised her head, a hint of sorrow flashed in her eyes however a moment later those eyes burned with hatred.

"It pains me to live but I have to, until I see that man die."

Leo sighed and asked

"How are you living among humans?"

"My main profession is a doctor."

"I see, just like Shinobu here."

Tamayo looked at Shinobu and asked.

"You know medicine?"

Before Shinobu could reply Leo interjected.

"She is the best doctor I have met so far, her ability to make drugs and other medications are top notch as well."

Shinobu faintly blushed hearing his praise, a sweet feeling rose from her heart.

Tamayo's eyes sparkled for a second.

"Shinobu-san, it's a bit rude but, I have a research I have been doing for the past three hundred years, can you take look at it and tell me what you understand."

"Hm, ok?"

Shinobu tilted her head in confusion, Tamayo looked at Yushiro who took out a stack of papers bound by thread from a nearby wall and give it to Shinobu.

At first Shinobu didn't care much for it but as she continued to flip through the pages her expression changed. She became solemn and the rate at which the pages flipped turned slow.

After twenty minutes...

"Incredible! How did you come up with such a theory?"

Tamayo for the first time showed a bit of happiness and said.

"A few blood samples I accidentally collected gave some unexpected results which sparked my inspiration."

"But can it be done? I mean a thousand year had passed since Muzan appeared and no one was able to do it."

"I am close to completing my research, I just need few samples of those demons close to Muzan in terms of strength."

Leo who was having a hard time understanding their conversation raised his hand and said.

"Speak in a way I can understand."

Shinobu turned her head and said excitedly.

"She has found a way, a way to turn demons back to into humans!"