Genius Isekai Mage

Rei slowly opened his eyes to a bright, blinding light. The light finally dimmed down after a few seconds, and he sees a woman looking down at him.

"□■□■□¤☆▪︎☆●■■□□!" The woman smiled down at him.

'What....What is this? Where am I? And why can't I understand her?'

Rei heard another incomprehensible voice, so he assumed that there were more people in the room along with him.

'Was I kidnapped? Let me try and move my arms...'

He raised his arms into the air, and they were...baby arms? He now understood, he had just been isekaied.

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It has been 15 years since I've been reincarnated. I found out magic exists in this world, the dream of many weebs including myself. I don't quite remember how I died, but the most probable cause would be a truck. My new name in this world is Rei Leythur, I didn't expect any less of such a name. I was born into the Leythur family, a well-known noble family.

I pick up a wooden sword from one of the stands, brandishing it and getting a feel for it with my hands.

"Are you ready, Rei?" A voice of a girl called out to me. It was my sister, Emilia. Emilia had long black hair that ended just above her waist.

"Yeah..." I sighed.

Magic in this world is unsophisticated. They all seem to stick to this one formula of using magic, but it's inefficient. I made a more efficient method, [Mana Heart]. I concentrate all my mana into my heart and use it as a core. It's very tedious and painful when creating the mana heart, but it is efficient. Not only do I have increased mana and regeneration, but it's spread across my body through the veins.

Currently, my studies are a bit difficult with the family bothering me and all that. But I will just have to make do.

"Come at me, Rei."

"Alright, sis."

I rushed towards Emilia, slashing vertically at her. Emilia blocked it and went for a counterattack, but I duck under it. I try and strike her in the legs. However, she reacted quickly and jumped up before kicking me in the stomach, sending me flying for a couple of seconds before I was able to catch myself.

"Not bad. You have improved."

"Thanks."

Fortunately, thanks to being born in a noble family, I have magic talent exceeding others. I've been able to learn over fifty spells since my isekai, as well as creating one of my own. Though, it's a bit hard to use as it requires three spells to be used at the same time. Hopefully, going forward, I can gain more proficiency in triple casting.

[Body Enhancement (Weak)]

[Haste (Weak)]

[Control Magic + Sight Enhancement + Enhanced Awareness] =

[Mirror Magic]

With this, I can see her moves and copy it. With such a weak body, it's only right to even the odds. I rushed at Emilia again, but this time, on the same level as her. We clashed again again and again. But what happens when your copy uses a different move?

Emilia slashed horizontally at me.

'Now!'

I dashed behind her, jumping up into the air before doing a backhand horizontal slash. Emilia was too slow to react to it and got sent flying. Emilia caught herself quickly, looking at me with a bit of annoyance.

"Rei, you're...using magic, aren't you?"

Whoops. She found out.

"Do you think you can fool me? You used Body Enhancement and Haste Magic!"

I scratched the back of my head. Well, she didn't recognize my Mirror Magic. I did create it after all. Emilia sighed as she put up her wooden sword.

"We'll end training for today."

"Alright." I did the same.

I went back inside the mansion, walking upstairs. I walked into my room, sitting down at my desk.

"Hm...what to do, what to do?"

I pondered for a couple of seconds before I got an idea.

"Oh, I know! I'm lacking some defense spells, so I should read some books on some!"

I jumped up from my bed, running to my father's library. Quickly, I found a book on barriers.

"Alright! Let's read!"

I read through the book quickly, flipping the pages at a fast rate.

"This is unnecessary long, but I understand it now. This won't take too long to do with my magic talent!"

I took a deep breath in, gathering my mana. In one take, I was able to form a barrier! To be honest, I wasn't expecting to get it first try. This barrier is a bit annoying, though. It pushes everything outside of it, which makes it impossible for hand to hand combat, which I prefer more.

"I wonder... would it be possible to make it thinner?"

I close my eyes, taking another deep breath. I began slowly contracting the barrier and making it thinner until it formed around me slimly.

"That works better. It's slim enough to where I can still pick up things and punch people. That's my favorite part."

I still wonder. Could you make it smaller? I control my barrier to form around my arm. I grit my teeth as I force it to be in the shape of a ball as small as my fingertip.

"Wow, that's tedious, even for me." I wipe the sweat off my forehead.

I hold the barrier within my fingertip, thinking.

"Can I throw you?"

I toss the barrier up into the air. Huh, I can! This gives me even more ways to use the barrier!

"Let's see how much damage you can do!"

I throw the barrier into the ground, the barrier cracking the ground beneath them.

"Pretty nice. With some additional spells, you can do some real damage! But I guess that's enough for now!"

I get rid of the barrier and put the book back on the shelf. Then suddenly, I heard a voice behind me.

"Rei! It is time to eat!" A maid said.

"Fine..."