The Snake Bone

Yamato Takeru dropped from the massive crater in the wall, landing firmly on the ground. As the iron fragments of the Kusanagi-no-Tsurugi peeled away inch by inch, the true form hidden beneath was revealed: the tailbone of the Great Snake. At that moment, Miketsu finally realized why the broken shard of the blade had transformed into a piece of bone after being separated from its host—because this was its original state.

"It is time... Now, I shall become the gate, crossing the boundary wall! I summon the descent of the Lord Deity’s incarnation! I... shall become one with the Lord Deity!" Yamato Takeru shouted fanatically, raising the skeletal Kusanagi-no-Tsurugi high. A surge of even more intense, purplish-red light erupted from within it.

Sensing imminent danger, Miketsu raised the Demonic Fang Blade and swung it downward, unleashing an Explosive Current Wave toward Yamato Takeru. The demonic tornado struck him directly, but the power released from the Kusanagi-no-Tsurugi formed a shimmering screen of light that blocked the attack, leaving him unharmed. Yamato Takeru had begun to tap into the vast reserves of power stored within the sword; as a relic of the Great Snake, the Kusanagi-no-Tsurugi's output capacity far exceeded that of the demonic blade in Miketsu’s hand.

Seeing the Explosive Current Wave prove completely ineffective, Miketsu’s heart sank. She gripped her demonic blade and flew straight toward Yamato Takeru, intending to cut him down directly. However, this time, the Kusanagi-no-Tsurugi in his hand was faster than her.

"Let your power return to this world! Incarnation of ancient calamity, the great Eight-Headed Serpent God!"

Facing the incoming Miketsu, Yamato Takeru did not swing his sword to meet her. Instead, he gripped the rigid, straight tailbone with both hands and thrust it directly into his own abdomen.

BOOM!

The moment the Kusanagi-no-Tsurugi pierced Yamato Takeru’s body, a terrifying shockwave exploded from him, pulverizing and scattering the rocks beneath his feet. Miketsu, who had already reached him, was caught directly in the sudden blast. She immediately raised the Demonic Fang Blade to shield herself from the flying debris, but her body was hurled backward, slamming into the far rock wall before she finally came to a stop.

"Ugh... This power..."

Enduring the pain from the impact, Miketsu stood up and looked forward with a grim expression. A storm of sinister, purplish-red energy was currently ravaging the entire underground space. At the eye of the storm, the center of this mutation, Yamato Takeru was trembling violently, his face contorted in agony. The massive energy the Kusanagi-no-Tsurugi had siphoned from the White Tiger Altar was now piercing through the boundary wall, opening a passage to the Void between the human realm and the Underworld. Something was emerging from the Void.

Under Miketsu’s watchful gaze, Yamato Takeru’s body—pierced by the Kusanagi-no-Tsurugi—began to wither rapidly like a deflating balloon. He became gaunt, nothing but skin and bones, before his very skin evaporated into a mist that was sucked into the sword. All that remained was a suit of armor and a skeleton that collapsed into a pile on the ground. Yet, the pale white tailbone remained suspended in mid-air, radiating energy. Having consumed Yamato Takeru’s flesh and blood, the second stage of the mutation began immediately.

Crack, crack, crack, crack...

The crisp sound of bone joints snapping echoed from the floating Kusanagi-no-Tsurugi. The once-straight tailbone began to twist and writhe like a worm, as if it had come to life.

Crack, crack, crack, crack...

The sound of the joints grew louder. The small tailbone swelled rapidly as it writhed. In just a second or two, the bone—originally the size of a longsword—had expanded to the thickness of a tree trunk and continued to swell at high speed.

As it expanded, other changes occurred. From the cross-section of the joints at the thick end of the bone, a new segment grew out directly. This new segment expanded along with the rest of the tailbone while simultaneously sprouting another segment at its tip. After several consecutive segments grew, sharp ribs began to branch out from the sides of the new bone.

In this manner, the tiny tailbone grew and expanded rapidly through its constant writhing. In a short amount of time, it had reached twenty meters in length, rivaling the size of the Demon-Faced Centipede, and it showed no signs of stopping.

Seeing this, Miketsu—who had just recovered from the direct hit of the powerful shockwave—immediately gripped the Demonic Fang Blade and flew toward the rapidly growing snake bone. Bolstering herself with Kishin power, she swung her blade with all her might, aiming to cleave the long snake bone in two. Her intuition told her that she had to stop this growth now.

THUD!

With a thunderous crash, Miketsu’s Demonic Fang Blade struck the middle of the snake bone squarely. The entire skeletal structure buckled under the massive impact, slamming into the side of the rock wall. Although the collision dislodged countless stones, the snake bone did not break. In fact, not even a single crack appeared where it had been struck. For the first time, Miketsu had encountered something that remained completely unscathed after a strike powered by her Kishin power.

Seeing that her slash had failed, Miketsu’s heart sank further. She immediately followed up with a barrage of attacks, striking the snake bone repeatedly and forcing its twisting form to crash against the cavern walls. Yet, from beginning to end, she was unable to leave even the slightest mark upon it. It continued to grow and expand despite the onslaught. It was now far larger than the Demon-Faced Centipede; its hundred-meter-long body was long enough to coil around the entire underground space, and yet its growth still hadn't ceased.

Under Miketsu’s assault, the snake bone finally retaliated. Its massive frame lunged at her ruthlessly. After dodging several strikes, Miketsu was nearly hit by a whip-like lash from the giant skeleton's tail coming from behind. At the last second, she spun around and blocked with her sword. Though she wasn't hit directly, she was knocked back a significant distance. During this exchange, Miketsu discovered a very serious problem.

"Causality... is blurred..."

Her causality vision, which she usually relied on in battle, was so blurred when looking at this snake bone that she could see almost nothing. The clear lines of causality she was used to seeing were absent; in their place was only a vague "tendency" she could barely sense. This made it impossible for her to use divination to predict and perfectly counter the incoming attacks as she had before.

Such a situation could only mean one thing: this snake bone possessed an incredibly high divine status—a status so high that Miketsu could not perform a direct divination upon it.

"Sigh... This snake... it couldn't really be a god, could it?"

As Miketsu lamented inwardly, the final joint of the giant skeletal serpent grew out. Then, a snake skull wider than Suzaku Avenue gradually formed from that last segment.

The massive skeletal head unhinged its jaw. Despite having no vocal organs, it let out a hiss that made the very world tremble.