"The meteorite is starting to melt! We're about to forge the sword blank!" Watanabe said excitedly.
After a long wait of seven or eight hours, the hardest material, the core component from the Village Hidden among the Stars, the meteorite from outer space, had finally begun to melt.
But then, in a stroke of either good or bad fortune, the Three-Tails' chakra began to be consumed at a furious rate. After seven or eight hours of continuous output, it was running on empty.
"Damn it. And they call this a Tailed Beast? It ran out of gas in just a few hours. Ptooey." Nagi spat. "This giant turtle is completely useless. Looks like if I want to forge a divine weapon, I'll have to use the Nine-Tails as fuel. Its chakra reserves are bottomless."
"It's alright, Nagi-boy," Watanabe said, stroking his goatee. "This old man anticipated this situation. We just need to supply the minimum amount of chakra to keep the sword blank from cooling. We can wait a few days for the Three-Tails' chakra to recover and then start again."
"Back in the day, when the Hidden Mist forged the Seven Ninja Swords, it was the same. Each blade took several weeks. All seven together took a full half a year. As long as the furnace fire doesn't go out and the sword blank doesn't cool, waiting a few days is fine."
As it turned out, the furnace also sealed and stored a portion of the chakra to maintain a minimum temperature, preventing the fire from being extinguished. This way, they wouldn't have to worry about stopping for a few days. Just like in regular blacksmithing, as long as a certain temperature was maintained and the metal didn't completely cool, it wouldn't be ruined.
But Nagi didn't have the patience to wait. He said to Watanabe, "Watanabe-san, if there was someone with chakra reserves comparable to the Three-Tails, would that be enough to finish forging this sword?"
Watanabe was taken aback for a moment, then he understood what Nagi meant. He intended to use his own chakra to finish it in one go.
"That should be possible. Every ninja blade requires a different amount of chakra. Based on this old man's estimates, if your chakra is as vast as a Tailed Beast's, you should be able to succeed in one attempt."
"Then let's continue," Nagi said. He sealed the Three-Tails away, then stood where it had been, placing his hand on the ground and pouring his chakra into the sealing array.
"Alright! Let's try to get it done in one go!" Watanabe said excitedly.
Ever since Nagi had transplanted the White Zetsu's left arm, and later captured a live White Zetsu, he had been extracting its marrow every day. After tempering it with Genya Shinazugawa's cells—his "treasure boy"—he had been injecting it daily. Now, his chakra grew more abundant with each passing day. White Zetsu's own chakra wasn't as much as a Tailed Beast's, but its regenerative ability was incredibly powerful. However, a strange thing happened when White Zetsu cells were injected into the body of an Uchiha: an incredible biochemical reaction occurred. Just as Madara had fused with the First Hokage's cells to obtain the power of all creation, when an Uchiha injected White Zetsu cells, their already mature, fully-grown body would undergo a second stage of development, and their chakra would increase dramatically.
Right now, Nagi's chakra reserves couldn't compare to the Nine-Tails, but they were greater than the One-Tail's, and close to the Three-Tails'. So, like a Tailed Beast, Nagi poured a continuous stream of his chakra into the furnace, leaving old man Watanabe staring in stunned silence.
Finally, just as Nagi was debating whether to open his Yin Seal to continue supplying chakra, Watanabe suddenly shouted.
"That's enough! The chakra is enough! The meteorite has completely melted! Now we begin the shaping and hammering!"
Watanabe excitedly circled the furnace, pressing here and there. Unlike the imagined scene of a blacksmith hammering a sword blank on an anvil, Watanabe was using the furnace's sealing jutsu to do the hammering. When he pressed a spot on the furnace, Honoka, following his instructions, would control the seal in that area, using the sealing jutsu to hammer and strengthen the sword blank inside. Then Watanabe would direct her to the next spot, and Honoka would nod and continue to manipulate the seals. The two of them worked in perfect harmony, with no need for Nagi to interfere.
"Alright! The sword blank is formed! It's time to take it out!" Watanabe announced excitedly. "After it's out, the final step is to quench it in the water from the summoning island, which is full of natural energy. Then the sword will be a success!"
Just then, the sky outside the sealing chamber suddenly filled with dark clouds. Then, a thousand bolts of lightning descended from the heavens, striking the outside of the sealing chamber.
BOOM!
The ground shook violently. Nagi felt it, and Watanabe's face changed drastically.
"So the legends are true," he said, his face pale with shock. "They say that when a divine weapon is born, the heavens will send down lightning, as if trying to prevent such an object from appearing in the mortal world. This is bad, Nagi-boy! The next part will be dangerous! As soon as the sword blank comes out, the thunder tribulation will destroy it! You have to find a way to block the lightning and keep it from destroying the sword, or all our work will be for nothing!"
Nagi nodded. "Don't worry, Watanabe-san. Watch me."
He closed his eyes for a moment. When he opened them again, the Yin Seal on his forehead had been released.
"Yin Seal: Release! Susanoo!"
At that moment, the lightning had already split the mountain open. The roof of the sealing chamber was blasted apart, and Nagi's Susanoo just managed to block the blow.
"It's coming out! The sword blank is coming out! You have to hold on, Nagi-boy!" Watanabe shouted excitedly.
Nagi gritted his teeth. Each bolt of lightning was more ferocious than the last. Even the Susanoo's absolute defense, which was like a turtle shell, couldn't hold. Wait a minute... a turtle shell...
A flash of inspiration struck Nagi. He released the Three-Tails once more. Then, before the next wave of lightning could strike, he cloaked the Three-Tails in his Susanoo, imitating Madara cloaking the Nine-Tails.
BOOM!!
The final wave of lightning, a flash of light so bright it could be seen for hundreds of miles, like the tribulation of a Mahayana-stage cultivator, struck the Susanoo-clad turtle with its full force. The Three-Tails let out a pained shriek, and the smell of burnt flesh filled the air. But the turtle, the most defensive of all creatures, its shell reinforced by the Susanoo, had withstood the tens of millions of volts of lightning from the heavens.
Just then, old man Watanabe's ecstatic voice came from below. "Nagi-boy! The quenching is complete! Your sword is ready! Catch!"
A dark shadow flew towards Nagi. He caught it steadily. It was an unremarkable katana, its blade crimson and still steaming. But the moment it was in his hand, he could sense its extraordinary power.
"Nagi-boy, you can use it now to test it against the lightning in the sky! Now that the sword is forged, it won't be so easily damaged. The lightning in the sky has already weakened a lot. A baptism of lightning will be good for the sword!"
"Alright." Nagi took a breath and coated his body in a layer of Susanoo. He wasn't the Raikage; a single bolt of lightning could turn him to charcoal.
The dark clouds in the sky began to disperse. As the last bolt of lightning fell, Nagi leaped up, raised the divine sword in his hand, and swung it with all his might.
BOOM!
Time seemed to freeze in that moment. The lightning was cut in two by Nagi and his divine sword, scattering in all directions.
When Nagi landed, the lightning in the sky had completely stopped. Only faint dark clouds remained, as if the lightning storm had just been an illusion.
"Success, Nagi-boy! Success! Hahahaha!" Watanabe cheered.
"That's great, Nagi-nii! The sword is finally a success!" Honoka said happily, wiping the sweat from her brow. She was also exhausted after controlling the sealing jutsu for more than ten hours.
"Give your treasured blade a name," old man Watanabe said, wiping away his own sweat.
Nagi thought for a moment. "It has just cut lightning. Let's call it... Raikiri."
Nagi would never admit that he was bad at naming things. He just thought the name Raikiri sounded cool...
"Raikiri. A good name," Watanabe said, stroking his goatee.
"According to my observations, a part of the Executioner's Blade's regenerative ability has been successfully fused into Raikiri. In the future, any small nicks on the blade can be repaired by absorbing blood, just like the Executioner's Blade. But as for its other abilities, you'll have to explore those yourself..."
The sharper a blade, the more likely it was to get small nicks on the edge during a clash, because the edge was so thin. That was why most swords weren't forged with an overly thin edge.
After that, Watanabe took out a pre-prepared metal hilt and attached it to the tang of the sword. Then he wrapped the hilt in a layer of linen cloth to prevent it from slipping. With that, the sword was complete. Oh, and the scabbard. The scabbard had been made according to Nagi's specifications, a mixture of lead and other metals, with the innermost layer being lead, because he was still a little wary of the radiation. But Watanabe had said that any harmful substances should have already been refined away by the immense chakra.
And so, a divine weapon that looked like an unremarkable cross between a katana and a Tang dao was born.
Nagi ran his hand over the blade with joy. He felt a close, blood-like connection to it. And why not? Half of it had been forged with his own chakra.
"Nagi-nii, want to go outside and try it out?" Honoka suggested cheerfully.
"Yes. I'll go outside and try it out." Nagi smiled and nodded, walking out of the now half-ruined secret chamber.
Outside, Kimimaro had been waiting for a long time. The heavenly lightning had worried them greatly.
"Sensei, did you succeed?"
"Nagi-nii, are you guys alright?"
Nagi nodded, smiling as he held up the unremarkable, dark-colored longsword.
"Success. Its name is Raikiri."
"That's great!"
"Congratulations, Sensei."
Nagi took a deep breath. "All of you, step back a bit. I'm going to test its power."
Sun Breathing, First Form...
As Nagi began to practice his swordsmanship, brandishing Raikiri, he felt a difference from his old Nichirin Blade. The treasured blade felt like an extension of his own body. And it had its own enhancements. As Nagi moved, the sun ore from the world of Demon Slayer, with its yang attribute, began to exert its power. The absorptive properties of the Executioner's Blade began to work, and the surrounding light began to dim, because the sunlight was being absorbed by the sword... Then, the blade began to turn red, and finally, under the influence of the Sun Breathing, it caught fire. No, it was a searing light. A Nichirin Blade, burning with a flame-like aura, had appeared.