Focus on one thing! Reach the pinnacle!

Infinity Castle, eastern section.

The wind howled in his ears.

His golden haori flapped wildly as Zenitsu Agatsuma plummeted, holding on to a grim-faced Yushiro.

The Twelve Kizuki are all badly injured and need time to recover. But according to Brother You's assessment, there's very little chance Muzan Kibutsuji was hurt in the explosion. That means...

Muzan Kibutsuji is at full strength right now.

If any squad runs into him at the outset, they'll very likely be wiped out.

My mission is to prevent that from happening.

His ears twitched slightly as he thought clearly through the current situation.

If I'm too slow, we might lose this battle. I...

No, I absolutely won't let that happen. Even if I die, I have to complete the mission!

It's only certain death. Burn your heart, burn your will, burn your life. Zenitsu Agatsuma, you can do this!

His eyes shone with a frightening intensity. Tiny electric currents danced over Zenitsu's skin, and a crimson mark spread from his cheek to behind his ear, like electricity tearing through the night.

Zenitsu activated his Demon Slayer Mark without hesitation!

Even if the price was never living past twenty-five.

Thunder Breathing represented ultimate speed and instantaneous bursts of power, yet the Demon Slayer Corps currently had no Thunder Hashira.

When Zenitsu received this mission from Lu You, he had been bewildered.

What do you mean, if I make a mistake here, the entire Demon Slayer Corps could be wiped out...?

"Zenitsu, we chose you because we all believe in you. You may always seem timid and cowardly, but your heart is resilient, kind, and strong.

"Don't worry, and don't let it weigh on you. Even if the entire Demon Slayer Corps is wiped out, I'll still kill Muzan Kibutsuji."

That was what Lu You had told him.

Even with a Hashira-level swordsman like the Sound Hashira right there... they still gave this mission to me...

Everyone...

"So how could I lose?! How could I possibly lose?! I absolutely won't allow it!"

His eardrums throbbed. Blood vessels filled Zenitsu's eyes as countless sound waves flooded his mind at once.

"Where? Where is it? Where's the sound of the biwa? Damn it, hurry!"

There were demons roaring, swordsmen locked in fierce combat, claws ripping through flesh, and blades severing heads. Chaos and noise.

The faint vibration of strings was so very weak, but Zenitsu still heard it.

His eyes immediately lit up. He hoisted Yushiro onto his back, white streams of air hissing from the corners of his mouth like rumbling thunder.

"I found her! Yushiro, we're heading out right now. Sorry for the trouble, but put those on me!"

"So fast," Yushiro said in surprise.

This guy is more dependable than I imagined.

Without the slightest hesitation, he stuck paper talismans inscribed with mysterious patterns onto both of them. Suddenly, their presences vanished.

"Thunder Breathing, First Form: Thunderclap and Flash! Godspeed!"

BOOM!!!

A savage, thunderous roar erupted. With that explosive boom, Zenitsu became a brilliant golden streak, shooting straight ahead and crossing a vast distance in an instant.

Nakime gently plucked her biwa strings, deliberately controlling the distance between the Demon Slayer Corps swordsmen and the Upper Ranks.

The Upper Ranks were still recovering. If a Hashira-level swordsman caught them now, they could essentially be declared dead.

Fortunately, the Upper Ranks had extremely powerful regenerative abilities. They would likely recover completely before long.

She did not actually want to bother with these Upper Ranks. After all, every pluck of a string meant using her Blood Demon Art. But without some micromanagement, she always felt they were all good for nothing.

This family would fall apart without me.

Normally, she could sense the positions of everyone inside the Infinity Castle. As long as she deliberately adjusted the terrain, no one could reach her.

"That man is dangerous. He must be banished somewhere farther away..."

To Nakime's senses, Lu You's presence was like a brilliant sun constantly radiating terrifying heat, towering and boundless. Even without deliberately searching, she could sense him clearly.

She gently plucked the biwa. Lu You, who had been strolling along at leisure, calmly watched his surroundings shift rapidly and gave a soft chuckle.

"Coward."

Of course, Muzan could not possibly know what Lu You was saying. Even if he did, he would not have been angry. He was the type to use any means necessary to achieve his goals.

Even with an absolute advantage, he still wanted the other demons to wear down the Demon Slayer Corps swordsmen further.

He had once been arrogant, until Yoriichi Tsugikuni slapped him awake.

Lu You was exceedingly strange, so Muzan did not want to fight him unless absolutely necessary. A hundred years later, he could be invincible in this world again. What was wrong with that?

"I understand your orders, Lord Muzan."

Nakime lightly plucked her biwa, her face expressionless beneath her long hair.

She did not know that a brilliant streak of lightning had already approached from behind her and stopped at a safe distance, waiting for its chance.

Breathing softly, Zenitsu set Yushiro down, then readied himself, gripping his Nichirin Blade with both hands.

He knew he had only one chance. If he failed, she would certainly be on guard, perhaps even constantly changing locations. Succeeding then would be extremely difficult.

The mark on Zenitsu's face blazed. He drew a long breath, his lungs expanding as surging power coursed through his entire body.

Since the intensive training began, he had passed every exercise as well. He had honed his Breathing Style to its utmost limit. It would be no exaggeration to say he could rival a Hashira now.

But only he and Lu You knew.

What had consumed the most of his energy was not the exercises in the intensive training, but his preparations for this very moment.

"Zenitsu, since you can't learn the other Thunder Breathing moves, hone the First Form to its absolute limit.

"Focus on one thing, and reach the pinnacle!"

"Only when you're too fast for even demons to react can you succeed."

Recalling his grandfather's and Lu You's words, Zenitsu's arms became wreathed in tiny electric currents.

Crack...

His skin seemed to burst, beads of blood seeping out as he strained every inch of muscle far beyond his limits.

"Thunder Breathing, Seventh Form: Thunder God!"

This time, I won't back down!

His eyes locked onto the raised platform a short distance away.

In front of that enormous folding screen, a woman was continually playing a biwa. He could clearly hear her breathing, her blood flowing, and her heart beating.

"I'm going in."

BOOM!!!

A violent, earth-shaking thunderclap rattled the surrounding platforms. Yushiro's ears rang as he stared in shock at the figure that had vanished from beside him.

A dazzling golden radiance shot straight toward Nakime's back, smashing the folding screen to pieces in an instant.

Danger!

The moment Nakime heard the sound behind her, she immediately moved to pluck the strings of the biwa in her hands.

It's fine. That lightning is still some distance away. I only need to change locations...

Squelch!

But an arm, carrying a biting rush of wind, slammed savagely into Nakime's body, even as the sharp crack of breaking bone rang out.

How is that possible?!

It was clearly still some distance away!

No, more importantly, why is he here?!

Blood pouring from his entire body, Zenitsu suddenly shouted, "Yushiro!"

Zenitsu had long since practiced this move to the point where his body could move faster than the lightning itself!

He would arrive before the visual effects.

"You don't have to tell me! Blood Demon Art!"

Veins bulging across his head, Yushiro instantly controlled the blood that had entered Nakime's body, sending it straight into her head.

Then he decisively controlled Nakime to perform two actions!

First, move the Infinity Castle to the surface of the Valley of the End!

Second, immediately teleport Lu You to Muzan Kibutsuji's location!

Sensing the abnormalities in Nakime and the Infinity Castle, Muzan's expression changed drastically. Without hesitation, he ruthlessly detonated the demon blood inside Nakime.

Bang! Nakime instantly burst into scattered flesh and blood!

But...

It was already too late!

"It really has been... a long time, Muzan Kibutsuji."

A teasing voice suddenly sounded behind Muzan. A figure in white was already slowly drawing his blade.

Muzan whipped his head around.

Lu You smiled.

"You did very well, Zenitsu, Yushiro. Leave the rest to me."