"What... is that?"

Rui clung to Muzan's pant leg, and watched in awe as the long, mechanical beast gradually came to a complete stop- emitting steam.

"That is a train," his master's smooth voice answered. "It is a mean of long distance transportation for the humans... and the preferred hunting ground of the man I'm going to introduce you to. Come."

He put a gentle hand on the boy's shoulder, and guided him into the dining car, "Enmu."

There was the rustling of paper, and a young man peered over the top of the newsletter he was reading, "Evening, Master Kibutsuji and... company..."

He gave Muzan a quizzical look, and the latter sighed, "This is Rui. The boy I was telling you about... Just this once, I'm going to make an exception for a demon having relations with another OUTSIDE of the occasional meeting or an apprenticeship. I'm assigning you to be his guardian."

Enmu turned his attention over to Rui, who was captivated by his two-toned, turquoise eyes, "Hmmn... How old are you, kid?"

"Erm... Eleven. I was turned three days ago, though, if that makes any difference... How old are you?"

"Physically? I'm seventeen years old. Biologically, though...? I'm one hundred and two... Been a member of the Twelve Demon Moons for seventy years."

Looking at the kanji etched on Enmu's left eye, Rui could see that he held the position of Lower Rank One, "Have you held that position all those years, or did you have to work your way up?"

"Ha! I wish I could tell you that I've held my current position for seventy years but, sadly, that is not the case... It's not the case for all of us lower ranking demons. We have to eat more humans, gain more strength, and become more powerful to serve 'him'. If you can't do that, then you're about as good as dead. Many of my less fortunate companions have found that out the hard way... Others are demoted, and stripped of their number."

He patted the seat as a gesture for Rui to sit beside him, "Join me, why don't you?"

Rui looked to Muzan for permission, and the man grunted, "I won't be able to join you two as I have... more professional matters to attend to, but I trust Enmu to care for you. Good luck to both of you, boys."

With that, he tipped his fedora and swiftly exited the car- slashing the neck of a passerby before disappearing into the crowd. Rui's jaw dropped when he saw that the passerby had been turned, and was going on a rampage, "Di- Did you see-?!"

Blood spattered the window as the train began to pull forward, and Enmu took a sip of his tea, "You're a demon yourself now, kid. Better get used to the crimes and bloodshed that come with it."

"... You said that you have been a demon for a total of eighty-five years? Do you have any memories of your human life? Wish you could ever go back?"

Enmu sighed, "I remember bits and pieces. The longer you've been a demon, unfortunately, the more memories you lose... As far as me wanting to go back to being human-?"

He paused- looking around and up at the ceiling anxiously- before whispering into Rui's ear, "- The only reason why I became a demon was self preservation so, to answer your question, yes... I miss being able to feel the warmth of the sun on my face. Smell wisteria blossoms without feeling sick to my stomach. Actually love someone, and not just use them for my own entertainment. I just... want my family back..."

"I do, too...," Rui hung his head sadly. "Despite what 'He' told me about my parents not loving me just because they tried to kill me, I know they did. I see now that the only reason why they tried to kill me... is to prevent me from turning into... this. A monster..."

Enmu thought for a moment before cautiously pulling the boy into his side, and was relieved when Rui rested his head on his shoulder, "You're not a monster, kid. You're just... misunderstood. We both are... If I'm going to be honest, Master Kibutsuji is the real monster here."

"Why's that?"

"Think about it, kid. He wants me to 'raise' and train you to become a member of the Twelve Demon Moons yourself and, just by looking at you, I can see why. Despite the fact you retained the appearance of a scrawny, sickly boy, your aura is powerful. Almost on par with mine... You could very well work your way up to Lower Moon Two if you wanted. But here's the thing... Do you know why Master Kibutsuji created the Twelve Demon Moons?"

Rui shook his head, and Enmu continued, "We have been given three tasks to complete by His command: to find the Blue Spider Lily, destroy the Demon Slayer Corps, and serve Him with suicidal devotion to ensure success... We weren't 'saved' by Him, kid. At one point or another, we'll lose all of our memories about our parents, siblings, and friends. Hopefully, we're 'put down' far before that happens..."