Reincarnated as the Heroine’s Big Sister, but My Little Sister Fell for Me Instead - Chapter 12

Edvard spread out the documents as he spoke.

“To maximize the efficiency of mana interference, the more points of contact between the casters, the better. Hands alone don’t provide enough surface area. Theoretically, the areas closest to mucous membranes are—”

“I understand,” I said, cutting off Edvard’s explanation.

Edvard closed his mouth. After a brief pause, he said, “Understood.”

Lian was looking at me.

Her expression said she had heard. It also said she understood. But she showed no emotion beyond that. So, I couldn’t read any further feelings.

“We have an hour until sunset,” Edvard said. “I’ll go prepare the recording equipment. Meet me behind the old building in thirty minutes.”

His footsteps faded away.

In the library basement, we were left alone.

The area behind the old building was bathed in the evening light.

It was a place with many trees, where the stone pavement still bore traces of old magic circles. People rarely came here. It was the perfect spot for a secret experiment.

Edvard finished preparing the recording equipment and stood a short distance away. “No need to call out. Let me know when you’re done.”

With just those words, he opened a book.

Lian and I faced each other.

The evening light dyed Lian’s profile orange. Her hair swayed slightly in the breeze. She was a head shorter than me.

“Let’s confirm the procedure.”

“Yes.”

“I’ll deploy the interference magic first. Then, Lian, you’ll apply your light mana to its boundary. To increase the points of contact—”

My words stopped for a moment. Silence flowed between us.

“We need to get closer.”

“I know.”

Lian said it quietly. She didn’t seem flustered. Her face looked like she was accepting it as a research procedure. That only highlighted the problem on my end.

“If you don’t want to—”

“I don’t mind.”

“I see.”

“What about you, Sister?” Lian looked at me. “Do you mind?”

I didn’t answer.

I didn’t mind. But putting it into words felt like crossing some kind of line.

“…Let’s begin.”

I drew out my mana. Inwardly, I gathered dark mist into my palms. I thinly deployed an interference field around my body. I increased its density compared to last time. The presence of my own mana clung to the outside of my skin, creating a slippery sensation.

Lian took a step closer.

Light mana touched the boundary of the interference field. It was warm. It felt comforting, almost like embracing a lover.

Lian took another step closer. Light mana entered the interference field. Darkness and light began to mix and circulate. Even though this was happening outside my body, my insides were reacting.

Another step.

We were now close enough to feel each other’s breath.

There were eyes looking up at me. Calm eyes. But behind them, something unsteady was swaying.

“Sister.”

“What is it?”

“I’m not scared.”

They were the same words she’d said the first time she saw magic in the night garden.

“I know.”

“I’ve never been scared. Not from the beginning.”

“I know.”

“Even so,” Lian continued. “I just wanted to say it once.”

I closed my eyes.

This wasn’t a moment to decide something. I’d decided long ago. I didn’t know when. Maybe in the garden of our childhood. Maybe in the hallway on the day of the entrance ceremony. Maybe on that night in the library when we first sat facing each other.

I was just confirming that decision tonight.

Gently, I pressed my lips against Lian’s.

They were soft. The first kiss was more pleasant than I’d imagined, and I was surprised.

Next, I noticed the scent of Lian’s lipstick. A faint, almost floral scent.

I didn’t open my eyes.

It felt like if I did, it would be over.

Lian hadn’t pulled away either. We were just touching. It wasn’t deep. But it was definitely there.

Inside the interference field, light and darkness were mixing. What had been happening outside my skin was losing its boundaries. It wasn’t cold, nor dark—only the tangible reality of simply being existed there.

At the same time, I felt emotions that could never be conveyed through words alone pass between us.

We pulled apart, neither of us initiating it.

I looked at Lian in the evening light. Lian was looking at me too.

We said nothing. It wasn’t that words were unnecessary—putting it into words felt almost crude. Lian’s face was flushed red all the way to her ears.

I released the interference.

The light mana slowly withdrew. Even after it vanished, warmth lingered as an afterglow. It was the same as last time. The difference was that this time, I wished it wouldn’t fade.

“Did you get the recording?”

Edvard’s voice came from a distance. He wasn’t looking our way. He was asking while still reading his book.

“We did,” I answered.

“Good.”

That was all.

On the way back, the three of us walked side by side. Edvard was talking about the theory of mana resonance. While giving occasional responses, I glanced sideways at Lian walking beside me.

Lian was walking straight ahead.

A bit of dusk remained behind us. The shadow of the old building stretched long.

“Sister,” Lian said softly, still facing forward.

“What?”

“Can we do it again?”

It was a pretext—for research. I accepted it as such.

“…I don’t mind.”

I sensed Lian smiling slightly. I couldn’t see her face.

Night was approaching. The traces of magic circles on the stone pavement had lost their light and faded from view. The residual warmth in my palms hadn’t yet cooled.