Merath set down his engraving tool and actually looked at her properly. She’d proven herself to be erratic and unpredictable in conversation and actions.

She had broken through his window. He didn’t even know what to think about that. It was something out of a fairy tail.

But right now? She was completely focused. Her eyes tracked his hands sharply. There was none of what he had come to expect out of her. There was no fidgeting, no distraction, and no impatience.

"Interesting." He murmured, returning to his work.

He picked up another component and began inscribing a different rune pattern. This one was more complex, with multiple interconnecting lines that had to be precisely aligned.

Lena’s head tilted slightly as she studied it.

Merath finished the inscription and moved to the next piece. He inscribed a similar but slightly modified pattern.

Merath decided to test the extent of her focus. "Did you notice what I did?"

"Mn." Lena took a moment to think. "That’s like the one you just did. But different. I don’t know how that affects it."

Merath paused. "Explain."

"The first one had the lines connecting at those three points." Lena gestured without touching. "This one connects at four points instead. Why?"

Merath smiled. This is what he was looking for. There was a very big difference between merely looking, and actually taking note of details.

"The three-point connection is for flow regulation." He explained. "The four-point connection is for directional control."

Lena nodded slowly, processing this. "So they work together? The first one regulates, the second one directs?"

"Exactly." Merath said. He pointed at one of the lines. "Look here. As you can see, mana here is directed up into the rest of the unfinished ring. Isn’t it missing regulation? How will we ensure functionality?"

"Um." Lena stared at the runes.

Hey...

The runes, the application of it, the flow...

It reminded her of something, very very much. Wasn’t this just circuits? It reminded her of then she was in grade school, and the teachers made them mess with electric circuits, making it flow through logic gates and regulators to turn a small LED on.

Lena slowly pointed at the engraved pathways.

"So this line carries the mana." She traced the air above it carefully. "Then this pattern limits how much goes through at once..."

Her finger shifted to the second rune. "And this part decides where it goes."

Merath’s tool stopped moving. "...Continue."

Lena frowned harder, mentally assembling pieces.

"If mana enters here without regulation, then when the direction rune activates..." She hesitated. "Wouldn’t it overload the next section? Unless another regulator catches it later."

"Look." She pointed at an exact section. "Assuming we want to continue the flow from here at the same volta- at the same mana density, then we can put a regulator right here."

"...Lena?" Merath slowly turned his head and looked at her.

"Yeah?" She smiled up at him, innocently.

Merath narrowed his eyes. "Are you sure you haven’t studied this before?"

"I haven’t!" Lena defended herself. "At most, it’s just a bit similar to something I did when I was a little girl."

"Right..." Merath took a deep breath. Well, she wasn’t lying, that much was true. Then... was Lena secretly a crafting genius? Or perhaps, he was underestimating her and she was just a genius in general. After all, her talent in magic was top tier, too.

That kind of intuitive understanding was rare. Even among his close disciples he taught accessory crafting too, most needed extensive explanation before grasping how different enchantment components interacted.

And yet, she had merely stared for a couple minutes, and she’d figured it out from observation alone.

Merath made a decision.

"Come closer." He said. "I’ll explain what I’m doing as I work."

Lena’s face brightened immediately. "Really?"

"Really." Merath confirmed. "But don’t interrupt unless you have a genuine question. I need to maintain concentration."

"I understand!" Lena moved closer, positioning herself where she could see clearly without being in the way.

Merath picked up the first high-grade mana crystal. "These will become the cores of the rings. Each crystal needs to be attuned to accept and store mana efficiently."

He held the crystal up to the light, examining its internal structure. "See these fracture lines inside? They’re natural channels where mana flows most easily. However, you’ll notice that I cannot use any of these. This is the most common scenario. I will have to artificially create my own."

Lena nodded, studying the crystal intently.

Merath used his magic to light up a theoretical path through the crystal. "As you can see, there very few places where we can create a fracture line without splitting the crystal. This path represents a spot where we can. As you can see, it is much better flow for our purposes than the natural lines."

With just enough applied force, thousands of calculations done instantly to find the correct spot, the crystal lightly fractures, a new line created through the structure. Afterwards, he began inscribing the first set of runes directly onto the crystal’s surface.

"The runes serve multiple purposes." He explained. "First, they expand the crystal’s capacity. Second, they passively subsist off the mana to create an enhancing effect. Third, they prevent catastrophic discharge."

"What would happen without that third one?" Lena asked.

"The crystal would explode if the wearer used too much mana." Merath said bluntly.

"Oh." Lena said quietly. "That’s important."

Merath nodded. "Very."

Merath finished the first crystal and set it aside, then picked up a second one. The process was similar but not identical. Each crystal had slightly different internal structures that required adjusted enchantments.

One at a time, he worked on all the crystals. Each one had a unique fracture made, with some not even requiring a new one to be made. As Merath engraved the runes on the crystals, he explained patiently how to do so without damaging or breaking the crystal.

Lena absorbed the information with awe. "It’s like I get it..."