(Risa POV)
"Hey, Rimuru? R-ee-muru!?" Milim sidled up to Big Bro as we headed back to town, poking at his squishy slime body in Shion's arms, "Why don't you become a demon lord? You're strong enough!"
"Why would I ever want that?" Big Bro responded immediately.
"Huh?" Milim responded, perplexed, "But… it's a demon lord we're talking about, here! A real-life demon lord! They're cool, right? Don't you think, Risa? Wouldn't you wanna be one?!"
"Well…" I said, a little hesitantly, "I'd wanna be strong…?"
Milim looked thunderstruck.
"It just doesn't seem like something that'd benefit me, you know?" Big Bro explained.
"But…! A lotta strong guys start seeking you out to fight!"
"Not interested. I already get in enough fights. Besides, people fear demon lords. I don't want people fearing what I'm building here, ya know?" Big Bro replied.
"Big Bro's kinda right… I'd like to fight you, though! That'd be fun!" I added.
"Let's do it sometime! But seriously, there's so much more to being a demon lord than that! You… get to boss majin around all the time?!"
"Doesn't that just mean you're bored?"
"Ah-!" Yup. Big Bro hit the mark, huh?
Aww, Milim was bored all the time? I knew exactly what to do! "Milim, how about I give you a tour! Show you all the really fun stuff we do in Tempest?" I asked, grabbing her by the shoulder.
"Really?! Promise you'll show me all the fun stuff?! Really fun?"
"Really, really fun!" I swore.
In response, Milim hugged me. "It's a deal!"
Big Bro held in a laugh, "Just… no starting fights in town, alright? Especially without my permission, I don't want anyone getting hurt."
"Okaay!"
…
(Rimuru POV)
It seemed that I could (mostly) leave Milim to Risa. I was a little worried, but (hopefully) it'd be fine, right?
Nothing like giving a nuclear bomb to a smaller bomb, right?
RIGHT?!
Yeah, I wasn't totally convinced, but since they'd disappeared together as soon as we'd gotten back to town, laughing joyously, I suspected that I didn't have a choice. Separating them at this point was likely impossible.
BOOOM!
…
(Risa POV)
BOOOM!
"Did you just call me 'little lady?' Do you want to die?!" Milim asked, a terrifying smile on her face. Almost instantly, Big Bro was there, giving the poor Gabil-in-a-hole a potion so that he didn't die.
It'd started when we'd met Gabil on the streets. Naturally, I'd stopped to introduce him to Milim, when he'd said "Hello, little lady! What's your name?"
Yeah, you probably shouldn't call a demon lord 'little.' Before I could blink, Milim had punched Gabil so hard that his Gabils had almost found themselves scattered across the street. In fact, it looked like her punch had been carefully measured to put Gabil as close to dead as possible without turning him into a red mist.
"OH! I saw my father waving at me from across the river!" Gabil shouted with a gasp as soon as the potion took effect, waking him up.
"Your father's alive, dummy. I'm glad that you are too, though." Big Bro told him with an eye roll.
…
(Rimuru POV)
After Milim forgave Gabil for whatever accidental slip of the tongue she'd nearly killed him over, I explained to him that she was a demon lord, and Gabil almost pissed himself.
At least this was a good learning experience for him, and he looked none the worse for wear. Good thing Gabil was so tough.
After extracting a promise from Milim that she'd refrain from 'greeting' people like that anymore, we agreed that she'd stay at Risa, her new 'bestie's' house. Since it was directly adjacent to mine, that was pretty perfect. Not as perfect as her leaving and not keeping me awake at night, just fearing when she'd pop off again with that temper of hers, but better than any other option.
Risa may not have very much life experience, making her act pretty immature, but despite her idiosyncrasies, she was pretty level-headed. She was a bit too wholly devoted to her curiosity, but she was pretty generally reliable outside of that. She'd be fine for keeping Milim from exploding, hopefully.
Scared me to think what they'd actually do together, but that was a better risk than leaving Milim alone.
Right?
That night, we had a feast to welcome Milim into town. As it turned out, Milim fit right in. People basically treated her like a stronger, more volatile Risa. They also practically worshiped me for 'taming' her. Apparently, she had a terrible 'wild child' reputation, like Veldora times four. Her nickname was the Destroyer, and everyone said that 'With her backing, Tempest is safe for all time!'