Reborn in Mushoku Tensei

"If you have five swordsmen and two of them die, how many do you have left?" I asked, watching Eris closely.

Eris froze, her face scrunching up in deep concentration. She raised one hand, holding up five fingers, then proceeded to beat down two of them with her other hand. Slowly, she counted the remaining fingers.

"You have three swordsmen left," she declared, flashing me a smug grin. Clearly, she thought she'd just conquered a monumental challenge. Honestly, her expression was kind of adorable.

I clapped my hands together with exaggerated enthusiasm. "Oh my god, Eris! It's only been a week, and you've gotten so smart! You deserve a treat!"

Right on cue, Sylphie walked over, and Eris immediately pulled her into a massive hug. Sylphie, ever the shy one, flapped her ears at Eris's urging, and I swear, I could practically see the heart-shaped pupils forming in Eris's eyes.

Before long, Eris had moved on to stroking Sylphie's ears, her touch lingering a little too long. Then, to my horror, she licked Sylphie's ear.

"Uhhh…" I mumbled, feeling a mix of secondhand embarrassment and awkwardness as Sylphie quivered slightly, her face bright red. Eris, however, seemed completely unfazed, as if licking someone's ears was just another part of life.

"I think we should take a break. I'll… uh… be back," I stammered, excusing myself and practically sprinting out of the room.

Once I was in the hallway, I let out a deep sigh, trying to shake off the awkwardness. "What the hell was that?" I muttered to myself. It felt… weird. Almost too weird. But then again, they were just kids Eris was nine, and Sylphie was seven. Maybe I was overthinking things. Then again, this is a world where everything feels like it came out of some bizarre anime logic.

As I wandered aimlessly, I accidentally bumped into Thomas, the butler. The guy was built like a mountain—wide and tall—and glared down at me like I was some kind of pest.

"Sorry about that," I said quickly, sidestepping him and moving on. But as I walked away, I couldn't help but glance back. Thomas had a grumpy demeanor, and if I remembered correctly, he was the one who eventually kidnapped Eris in the future. Definitely someone I needed to keep an eye on.

Eventually, I made my way to the library, deciding to spend some time being productive or at least trying to. I sorted through the shelves, scanning for anything that caught my interest. Ever since I'd arrived at this manor, the idea of building something had been swirling around in my head. Specifically, I wanted to build a motorcycle powered by magic.

The concept wasn't impossible, but the biggest hurdle was that I didn't fully understand how magic circles worked in this world. So, for the past couple of days, I'd been pouring over books on the subject, trying to absorb as much information as possible. With my photographic memory, I could read through the material quickly and retain everything, but understanding the practical applications took more effort.

Most of the books in the library were basic, covering things like elementary magic circles and how to layer them. I'd even come across some notes on magic crystals, which seemed relatively easy to use. But nothing had given me the breakthrough I needed.

Hours passed as I combed through the shelves, and just when I was about to give up, I spotted a worn, beat-up book tucked away on the bottom shelf.

"Oh? What's this?" I muttered, pulling it out. I dusted it off and flipped through the pages. My eyes widened as I realized what I was holding.

"This is exactly what I've been looking for!" I said aloud, unable to hide my excitement. The book detailed how to use magic circles for engineering and building purposes a goldmine for someone like me, a former engineering student.

Building the physical motorcycle would be easy; the challenge lay in integrating magic circles into the design. But with this book, I could finally make some real progress.

As I immersed myself in the pages, a voice interrupted me.

"Master Rudeus, Lady Eris and your assistant have been looking for you for an hour now," a maid said, bowing politely before leaving me alone.

My stomach dropped. I'd completely forgotten about them. Panic set in as I hurriedly closed the book and rushed back to the classroom. The last thing I needed was to get fired.

By the time I arrived, I was panting, slightly out of breath from running through the massive manor. When I stepped inside, I froze.

Sylphie was sitting in Eris's lap, and the two of them were looking over the study materials I'd prepared a couple of days ago.

"Oh, hey, Rudy!" Sylphie said with a bright smile. "Me and Eris have been doing the work while you were gone."

My plan to use Sylphie as a motivator for Eris had worked too well. At this rate, Eris was going to fall in love with Sylphie. Not that I could complain the results spoke for themselves. Even when I wasn't around, Sylphie could keep Eris on track.

"Wow, Eris," I said, feigning surprise. "You've been studying so hard! Do you want to take a break and practice swordsmanship?"

Eris shot me a withering glare, furrowing her brows. "For a teacher to take so many breaks is disgusting," she said, her tone dripping with disdain.

I dropped to my knees, my face a picture of mock despair. "I'm just trying not to overwork you…" I muttered. What had changed in this world to make Eris, of all people, enjoy studying?

Then Sylphie chimed in. "Come on, Eris! Just one more question. If you get it right, I'll let you nibble on my ear."

The moment those words left Sylphie's mouth, Eris's entire demeanor shifted. Her eyes locked onto the problem in front of her, her brain going into overdrive.

Minutes later, she slammed her hands down on the desk, grinning from ear to ear. "I'M DONE! YAY!"

Eris looked like some shady crook who'd just hit the jackpot, her grin almost perverse as she turned her attention to Sylphie, practically salivating.

I sighed. "This is getting out of hand…"