"Nel, Harribel, go up and wait for me."
Nanatsuki used a Kidō spell that allowed sound transmission underwater to inform Nel and Harribel to move away.
He had no idea how strong the presence beneath the lake was. If a battle broke out, he might not be able to protect his disciples.
Nel and Harribel looked worried but followed their teacher's command and swam away.
"Teacher... glug... be careful... glug..." Nel's voice was muffled by the water.
Once they were gone, Nanatsuki resumed observing the movements beneath the lake.
The large eyeball hadn't shown hostility yet. Nanatsuki wanted to see if it was possible to communicate with this strange spiritual entity.
He studied the eye carefully but couldn't glean any emotion from it.
Then, the eye deep within the molten trench began to rotate.
Its golden pupil locked onto Nanatsuki's position.
"My Lord:"
Nanatsuki froze slightly as a foreign voice echoed in his mind.
"My Lord... may calm the mind... and communicate with me..."
The unfamiliar voice sounded again.
It was cold and hollow, like something spoken by a machine devoid of feeling.
'So I can talk to it telepathically?'
Nanatsuki realized the voice must belong to the giant eyeball.
It didn't seem hostile.
But he had plenty of questions. Why did it refer to him as "My Lord"?
He didn't remember ever acquiring such a "servant."
'What are you? Why do you call me "My Lord"?' he asked inwardly, focusing his thoughts.
"I am a creation of the Soul King... thus a servant... of the Soul King..."
The voice of the eyeball answered.
'A creation of the Soul King...' Nanatsuki's brow lifted. 'But I'm not the Soul King.'
He couldn't find any memories related to this giant eye—not from his past life, nor from any record in Soul Society. Most records involving the Soul King were vague, steeped in grand narratives, with almost no concrete details about what the Soul King actually did.
"You are the Shadow... of the Soul King... and thus My Lord..."
'You can perceive the essence of my spiritual body?'
Nanatsuki's eyes sharpened. He was beginning to believe this eye truly was one of the Soul King's creations.
The moment he transmigrated into the Soul King's shadow, his consciousness had been born from within it.
And once he was cut off and sewn into Katori Batsu'unsai's Reishi Shell, he had become an independent being—like other Soul King remnants that had developed self-awareness.
But over all these years, apart from the Royal Guard who had personally implanted him, no one in Soul Society had ever realized he was the Shadow of the Soul King.
Yet this eyeball had.
"I am an instrument created by My Lord... I can sense His presence..."
The voice echoed again.
'Why are you here?'
"I guard the gate... the passage to Hell..."
'There's a path to Hell down here?'
"Indeed... My Lord tasked me with guarding it... Within this passage lies the sealed soul... of the Lord of Hell..."
'The Lord of Hell is sealed inside this passage? From what I know, his soul was split into three. Is this one of the pieces?' Nanatsuki's thoughts stirred as he recalled old research.
"I do not know about the others... Within this passage lies a sword... forged from the soul of the Lord of Hell... by stealing My Lord's power..."
"A sword… created from the soul of the Lord of Hell?" the eye added. "It should now be called... a Zanpakutō."
'A Zanpakutō belonging to the Lord of Hell!' Nanatsuki's heart trembled.
This was knowledge absent from all ancient records.
The war between the Soul King and Hell predated even the history of the Three Realms. Very few texts described it in any detail.
'Did the Soul King create you to suppress that Zanpakutō using Quincy power?' Nanatsuki recalled sensing Quincy Reiatsu from the eyeball.
"Indeed... The power of a Shinigami and that cursed blade share the same origin... making them more prone to corruption..." the eye answered.
'So the Lord of Hell once stole power from the Soul King... Could that be the real cause of their conflict?'
Nanatsuki speculated silently.
The eyeball didn't know. Its sole purpose was to guard the sword. The Soul King hadn't granted it detailed knowledge or intellect.
'If the blade corrupts Shinigami, would I be affected if I come into contact with it?' he asked.
A secret of this magnitude—how could he not be curious?
"Your current strength cannot suppress the cursed blade... Only by transcending the limits of a Shinigami or Hollow... and mastering Quincy power... can one resist its influence..."
'So I'd need to become a Transcendent… that's still far off.' Nanatsuki furrowed his brows, keeping the matter in mind. 'Even so, shouldn't the Soul King have destroyed the sword rather than seal it here?'
He figured a being like the Soul King should be able to destroy even a Zanpakutō forged by the Lord of Hell.
"The cursed blade summons Reishi from Hell... These Reishi pass through the gate... sink into the depths of the Forest of Menos... and become part of Hueco Mundo's foundation..." the eye replied.
'I see… That explains the abnormal number of Hollows in the Forest of Menos.'
It all clicked for Nanatsuki.
The Soul King was using Hell's blood to nourish the Three Realms.
By exploiting the cursed blade, the Soul King continually siphoned Hell's Reishi into Hueco Mundo.
Hueco Mundo had become a relay station. After entering it, these Reishi circulated through the Three Realms via Hollows and Shinigami activity.
'So this might explain why Hueco Mundo's Reishi hotspots keep expanding...' Nanatsuki rubbed his chin.
"My Lord... I sense it..."
The eye's voice returned. "The Quincy power gestating within you..."
'You can sense even that?' Nanatsuki raised a brow.
Indeed, there was Quincy power forming within his spiritual body.
He had extracted Quincy bloodline from Kurosaki Tsukiren using the Bloodline Extractor.
He'd underestimated the time it would take to nurture that power.
Perhaps due to high loss during extraction, he had only obtained a small amount of Quincy blood—so small it still hadn't fully formed even after years.
"My Lord..."
The eye spoke again. "I shall offer part of my power... to accelerate the growth... of your Quincy strength..."
'You can do that?' Nanatsuki raised a brow. This development was completely unexpected. The eye could help incubate the Quincy power within him.