Master Blacksmith in Demon Slayer

He used iron tongs to clamp the iron ingot and placed it on the anvil.

The forging hammer was right beside him. Gripping the red-hot ingot with the tongs, he took the hammer in hand, and an inexplicably familiar feeling stirred in his heart.

"This is the first weapon I, as a reborn... Tetsu no Sosuke, will forge! Then, let's begin!" After spouting that chuunibyou line, he brought the hammer down with a clang.

Ding!

Impurity -1

"Huh?"

Chapter 2: Furious Tempering

"Did I mishear? Sounded like something just now." Tetsu no Sosuke looked around—nothing was there. He lived in a somewhat remote area, and rarely did any friends play tricks on him.

"Must've misheard." He nodded, refocusing on the iron ingot in his hand.

Clang!

Impurity -1

"What the hell! No way I misheard that this time!!!" The sound didn't come from around him, but from right by his ear—seemingly inside his own mind.

He glanced at the forging hammer in his hand, then at the ingot on the anvil. Taking a deep breath, he put all his strength into it. Clang!

Impurity -1

"It really is!!" Tetsu no Sosuke was momentarily speechless. "Besides seeing the progress when heating the ingot, I can also hear the 'Impurity -1' sound when hammering. No need to doubt anymore! My golden finger is definitely... the Blacksmith System!!!!"

"So, I'm just destined to be a swordsmith, huh?" Tetsu no Sosuke silently questioned the heavens, then resignedly continued hammering.

With every strike, he heard the Impurity -1 sound in his ear. But as he kept hammering, the sound grew less consistent. Occasionally, a blow would land with no prompt, and over time, the prompts became rarer and rarer.

He also noticed that the iron ingot in his hand had cooled down. "Is it because the temperature dropped?" Thinking this, he shoved the ingot back into the furnace.

Once the temperature indicator rose back to the standard mark, he took it out and resumed hammering. It returned to the beginning—every strike brought the Impurity -1 prompt.

And so, aided by this sound, Tetsu no Sosuke began a cycle of repetition. Hammer, hammer, hammer, heat, heat, heat, then hammer again...

From noon until evening, with only brief breaks in between, he spent the entire time working that piece of iron.

"Tough piece to beat!" Tetsu no Sosuke rubbed his arms and sent it back into the furnace. "Good thing I've been forging since I was a kid—otherwise, this kind of high-intensity smithing would be hard to endure. Well, after this round, I should eat, right? Yeah, I'll keep going after dinner!"

Once the temperature was back up, he used the tongs to pull out the ingot he'd hammered hundreds, if not thousands, of times. Picking up the forging hammer, he looked at the ingot that had accompanied him all afternoon, and suddenly, an indescribable feeling welled up in his heart.

It felt like he'd grown close to this thing. Like it was a newborn child, and he... was slowly shaping it into form!

A surge of emotion—one he couldn't even name—flooded his heart. The forging hammer lifted instinctively.

The hammer fell, sparks flying.

Impurity -5

Strength +1

The sudden appearance of two prompts instantly snapped Tetsu no Sosuke awake. A warm current surged through his body, revitalizing his exhausted frame with fresh energy.

But those two prompts jolted him fully alert, leaving him frozen in place!

"What just happened?" He looked at the hammer in his hand, then at the ingot before him. "Why did I suddenly feel so close to it just now? Why did that one strike reduce impurities by 5 points? And... Strength increased by one?"

He moved his arm. Though subtle, he felt like he really had become more capable. "So, this golden finger doesn't just let me know exactly how much impurity this iron has lost—it can even boost my own strength?"

With that thought, he sucked in a sharp breath and struck again.

Impurity -1

No prompt about a power increase appeared, and the impurity had only decreased by a single point.

"No, no! This feels wrong!"

He shook his head. The sensation from that earlier moment was clearly different from this latest strike.

What was the reason?

"Not close enough?"

He stared at the piece of iron, struggling to sink back into that previous emotion, trying to get close to it.

But no matter how he looked at it, it was just a piece of red-hot iron, nothing more.