Disclaimer: I do not own any of these characters or either of the works this fanfic takes inspiration from. Credit for them goes to their respective creators.

This takes place post-Tenma war for That Time I Got Reincarnated as a Slime and at the beginning of the series for Welcome to Demon School, Iruma-kun.

This is my first time writing something like this so any friendly advice to improve my writing will be greatly appreciated! I have a hard time not using run-on sentences so sorry for that.

Punctuation Key:

"Spoken dialogue"




Internal thoughts/talking to Ciel

[[Ciel talking]]

{{Thought Communication}}

#Whispering/Speaking Quietly#


Rimuru POV

I sit in my office, staring out the window, the warm sun hitting my face. I can vaguely see the reflection of a beautiful young girl(?) in the glass, flowing silver-blue hair; large, golden eyes staring back giving an expression of boredom. My beautiful country lying before me, once just a small goblin village on the brink of annihilation, is now an absolute utopia. A gorgeous metropolis spanning as far as the eye can see, Tempest. Below I see people of many races, monsters, demi-humans, and humans, all intermingling, a bustle of activity. Despite the appearance of chaos, there is still a sense of order and serenity to it all. Tempest has reached the peak of what I believe to be perfection. With every one of my dreams all but accomplished, I, the Great Demon Lord Rimuru Tempest, sit there, pondering what to do next with my immortal existence. Suddenly, I hear a knock on the door and sense a familiar presence, snapping me out of my reverie.

"Lord Rimuru…?"

"Come in."

It's Diablo, my butler/2nd secretary who just happens to be the legendary Black Primordial demon. One of my strongest subordinates. He has a look on his face that I don't see very often; like he's nervous or apprehensive about something. His usual confident demeanor is nowhere to be seen so something must be very wrong, something he can't handle by himself.

"Is there something wrong, Diablo?" I ask, concerned about his odd expression.

"Sorry to bother you My Lord, but may I ask a favor of you?" replies Diablo, somewhat timidly.

I may have just said I was bored but the last thing I want is an emergency. Diablo can handle almost anything by himself and takes pride in that fact. If he is asking for my help, it cannot be for anything short of a disaster.

"S-sure…?" I ask, a bit hesitant to find out what mess he's brought to me.

"You see, I recently was contacted by an old friend of mine. He recently acquired a new grandson and would like me to meet them. Normally I wouldn't abandon my post for such a petty thing, but he made a troublesome statement that I feel the need to address."

"An old friend? Okaaay…"

I guess I was overthinking things again. Also, what the hell does he mean by acquired a grandson!? Sounds pretty sketchy, but since this is a friend of Diablo's of course he is gonna be a bit of a weirdo.

[[Master, it is likely that by 'acquired' he means adopted.]]

Yeah, let's just go with that, for my ease of mind at least. Diablo can have a strange way of putting things sometimes.

"So, you want my permission to go then?"

Seemingly mustering up some courage, Diablo clears his throat and says…

"Yes, My Lord, but that is only part of my request. He made the outrageous claim that this grandson of his is 'unbeatably adorable' and I could not help but take that as an affront to you, My Lord! Nobody can outclass my precious Lord Rimuru! I must show him the error of his ways and for that, I humbly request that you accompany me!" Diablo passionately begs as if his life depends on it.

Oh geez…what have I gotten myself into? This is worse than I thought! I'm glad Benimaru isn't in the room right now. I can almost hear him snickering…

[[He is correct. Nobody can beat your cuteness, Master!]]

Oh, come on Ciel! I'm an adult and a Demon Lord! Adorable and cute are not part of the image I'm going for here!

[[Hehehe… but you still are adorable though! #…and you're all mine!# *wink*]]

Whatever…and I'll just pretend I didn't hear that last part for the sake of my own sanity…

[[*giggles mischievously*]]

I currently look like a little girl so adorable is a way you could describe my appearance, much to my distaste. I could fairly easily take an adult form but looking around 12 just seems easier for day-to-day life. When I make myself look any older than that I tend to get 'unwanted attention' from people who don't know who I am, which can get annoying. I do take on adult form for official appearances and such though, otherwise, I tend to not be taken seriously by foreign diplomats and the like.

So, essentially Diablo wants to 'show me off' to his friend? How humiliating… I'm not some toy to take to show-and-tell with you!

This feels like it is gonna be a lot like when Shuna and the other women play 'dress-up' with me. Normally, I would refuse such an obnoxious request in a heartbeat, but Diablo rarely asks me for anything yet does so much for me. I guess I can give into him this one time as a reward for his hard work. Plus, I'm curious about what type of person Diablo would consider an 'old friend'.

"I guess I can go along with you this one time, Diablo. You've earned it." I say, hoping I won't regret this decision later.

"Thank you so much, My Lord! I cannot express how grateful I am that you would sacrifice your precious time for such a thing!" he exclaims, an expression of extreme excitement on his face.

Sheesh, the guy looks like he is gonna cry tears of joy, talk about overdramatic…although with Diablo that should be expected.

"Alright, just tell me exactly where we're headed to first."

"It is a place called The Netherworld; a realm inhabited by beings that are an offshoot of true demons. They still refer to themselves as demons but are a different kind of existence than the ones you have encountered. Having taken on a permanent physical form, they are more akin to majin than true demons such as myself."

"Very interesting, I never knew a place like that existed! When are you planning on meeting with this old friend of yours?"

"Would tomorrow morning work for you, My Lord? I must show him your unrivaled perfection as soon as I can!"

*sigh* "Yeah, sure. That works for me. Meet me here in my office again tomorrow please." I say, a little reluctantly.

It's not like I have anything better to do right now…

**The Next Morning**

Once again in my office, I start preparing for my trip with Diablo.

Might as well go full out with this… I think as I shrink down to an appearance of a 5-year-old, or at least close to that. I also change out of my Demon Lord garb into something more casual. This is even smaller than the original size of my human form before I fought the Orc Disaster. Diablo gives me a look of confusion.

"My Lord, what are y-?"

I cut him off. "You said you needed adorable didn't 'cha? Well, might as well go all the way with it, right?" I say with an evil grin that I'm sure is jarring when paired with my current appearance. Diablo raises one eyebrow, seemingly noticing something might be up.

I do have another reason for this change in appearance. Since I'm going out of my way for Diablo, I hatched a plan to have a little fun for myself along the way. Even after reincarnation, creating my own country, and becoming a Demon Lord/True Dragon, I still can't help myself sometimes when it comes to messing with people. That part of me will never change. I plan to not just have the appearance of a child, but to act like a child too (a spoiled brat to be specific), embarrassing dear Diablo in front of his friend!

Hehehe…I can't wait to see the look on his face!

[[Master, are you sure this little prank of yours is a good idea? You will be meeting with a total stranger, acting foolishly might cause problems for you.]]

C'mon, it'll be fine! I'm just having a bit of fun at Diablo's expense! It is a bit mean, but I'm sure he can handle it.


I sense that Ciel is shaking her head at me in disappointment.

I send Diablo outside, intending to meet up with him there in a few minutes for our departure from Tempest. I still have a couple of things to take care of before I leave so I tell him to wait for me. Soon though, I hear a knock, someone is standing at my door. Sensing the aura, I'm filled with a sense of dread, the grin on my face melting into an expression of anxiety.

Awwwww shiiit…


Did you tip her off to my plan Ciel!


Don't give me the silent treatment you little snitch! You did, didn't you!

[[…it is for your own good, Master.]]

I knew it! What the hell am I gonna do now!? I'm screwed!

"C-come in," I say, a bit sheepishly. I manage to plaster a fake smile onto my face, trying to hide my apprehension.

The door opens, standing there is a young woman with powder-pink hair and two slender white horns coming out of her forehead. Shuna, and on that pretty face of hers is that smile. A smile I, unfortunately, know well, one that looks sweet on the surface but lying underneath is a sinister air that strikes fear into my soul.

"Lord Rimuru, it has come to my attention that you plan on meeting with someone in a foreign land. Why have I not been informed about this? Proper procedures must be taken for things like these."

"I-it's just a little trip to meet with one of Diablo's old friends! It isn't anything big, so I didn't think it was necessary to tell you about it!" I frantically try to make excuses.

"Any time the sovereign of a nation leaves their country it is a matter of concern. You should know this by now, Lord Rimuru. Are you sure you don't have another motivation for failing to inform me?" she leans forward, bringing her face inches from mine, that creepy smile still on her lips, her pink eyes staring straight into my golden ones. The pressure behind that gaze is intense, even for me.

"I maaay have planned to have a little…um…fun while I was there…?" I say forcing a sweet, innocent smile on my face. I gotta use that cuteness to my advantage!

"As I suspected!" She snapped. "You were up to one of your immature schemes again! Don't you understand doing foolish things reflects badly on you and your country!" She shakes her head disapprovingly, folding her arms.

"Yes…I understand." I say, looking down at my (tiny) feet, feeling defeated. Despite being my subordinate, she's lecturing me like I'm a child. (I guess I do look like one right now but that's beside the point.) With her being my advisor on 'royal etiquette' I guess it makes sense.

"As long as you promise not to embarrass yourself at this meeting, I willpromise not to tell Shion you are going on a 'vacation' without her."

"I'll behave, I promise." I give in to her blackmail. The last thing I need is Shion begging to come with me. We don't need a repeat of that one time I took her with me to Dwargon only for her to pass out drunk in front of their king, Gazel Dwargo. Shion has become much more mature over the years but, for a personal meeting like this, extra people coming along tends to spell trouble.

"In that case, enjoy your little trip, My Lord." She bows before leaving the room, sure that her message has gotten across.

Phew! I thought I was a goner there…that was dirty of you Ciel!


Nothing to say in your defense, huh? Well, whatever…I guess it doesn't matter since I got off the hook for the most part.

Using Spatial Movement, I teleport to Diablo who's patiently waiting for me outside.

"Diablo, let's go before I get any more…unwanted guests."

He looks at me a bit puzzled but then nods before conjuring up an elaborate-looking gate leading to the Netherworld his old friend resides in.

I wonder what kind of place this 'Netherworld' is, sounds dangerous. Not that I have anything to worry about when it comes to dangerous things. I think to myself as I step through the gate into the unknown, following closely behind Diablo.