Originally, Tsunayashiro Tokinada had no need to seek out these two swords. After all, his own Zanpakutō was far from weak. However, circumstances had forced his hand. With his murder of Uta Kuwa revealed and Central 46 summoning him for judgement, his Zanpakutō had been temporarily confiscated.
Until he was cleared of suspicion, his blade would not be returned.
This was one of the standard measures Soul Society used to reduce the threat posed by a Shinigami – seizing their Zanpakutō to strip their power.
Additionally, many Shinigami who had been dismissed from duty would have their Zanpakutō confiscated as well. In Soul Society's long history, however, there were few cases of Shinigami being dismissed outright. Most who faced dismissal were imprisoned in the Maggot's Nest under strict guard.
Thus, Tsunayashiro Tokinada found himself without his Zanpakutō, and regaining it through legal means was virtually impossible.
To defend himself, he had only one choice: search for the two hidden swords within the Tsunayashiro estate.
If he obtained them, the loss of his own Zanpakutō would no longer matter.
Using clues he had collected over many years of secret searching, Tsunayashiro Tokinada acted swiftly.
He left Tsunayashiro Tokio's corpse lying on the floor of his room, making no effort to conceal it. He had no time for such things.
The Tsunayashiro family's estate spanned a vast area.
The branch houses and the main house shared the same grounds, though the main house was heavily guarded.
It was natural. While many Tsunayashiro clan members were Shinigami, a significant number possessed no spiritual qualifications. For their protection, guards were always stationed nearby.
But to Tsunayashiro Tokinada, these guards were meaningless obstacles.
He knew every inch of the estate and its patrol patterns. Combined with his immense strength, avoiding detection was easy.
Had he chosen to become a Gotei 13 Shinigami, Tsunayashiro Tokinada's power could have secured him a captain's seat.
Using Shunpo, he advanced through the darkness, reaching the core of the main house in mere moments.
Finally, he stopped before a room. A translucent spiritual mask materialised before him.
"A barrier?"
A smirk curled across his lips.
Silently, he began weaving Kidō incantations.
With precise control of Kidō, Tsunayashiro Tokinada broke through the barrier effortlessly.
He stepped forward and saw a black lacquered box resting upon an ornate pedestal.
Upon its lid was a binding charm – another layer of sealing.
This time, breaking it took slightly longer, but ultimately it fell under his skilled Kidō arts.
As the box creaked open, an intense wave of deathly Reiatsu burst forth, flooding the room with killing intent and suffocating darkness. Within lay a Zanpakutō in sealed form.
Unlike typical sealed Zanpakutō with silver steel blades, this sword's blade was stained a deep, blood-like crimson.
Once, a genius of the Tsunayashiro family had wielded this blade. His brilliance had illuminated an era.
At that time, the Tsunayashiro clan stood unmatched above the other Four Great Noble Houses, ruling as the undisputed supreme noble family.
That genius, though born into a branch house, possessed such formidable might that even main family elders showed him reverence.
However, he still underestimated the depravity of the Tsunayashiro lineage.
This was a family stained with inherited sin – a clan that once dared to murder the Soul King for its own gain.
The genius' ideals were too naïve. He sought to befriend both nobles and commoners alike, thinking that bridging such worlds would strengthen the Tsunayashiro family.
But his relationships and ideals brought no tangible benefit to the clan's ruthless leaders.
And so, the patriarch of that generation conspired against him.
In the end, the genius fell, undone by the very family he sought to uplift.
Normally, when a Shinigami died, their Zanpakutō would lose its Reiatsu supply and degrade permanently. Even if another Shinigami poured spiritual power into it, the blade would never return to its former strength or true form.
But this sword was different.
It was like the ancestral sword passed down through Tsunayashiro's generations, able to remain dormant yet preserved for future use.
Of course, for an outsider to wield it came at a terrible cost.
That cost was the sacrifice of one's own soul, used as fuel to drive its power.
"Only this sword remains here?"
Tokinada narrowed his eyes.
"It seems the current Patriarch carries the other blade on his person."
Although the Patriarch seldom used that ancestral sword, he kept it close as his trump card.
Naturally, he could not carry both swords at once.
After all, it was impossible to wield two such cursed blades in battle. The price of even one was nearly unbearable; activating both simultaneously was suicide.
"But it doesn't matter. I am unafraid to bear this price."
Tokinada's voice was low and resolute.
He reached forward, grasping the crimson blade's hilt.
Instantly, a wave of murderous aura surged into him. His spiritual power felt as though it was being drained into the blade, while a deeper, more horrifying sensation emerged from his soul – the feeling of it being gnawed away.
This sword was monstrously powerful.
In its past owner's hands, it had slain countless powerful beings – Shinigami captains, Gillian-class Menos, Adjuchas, even Quincy. Its killing edge spared no one, developing into a Zanpakutō of absolute destruction.
To control it required immense force of will and Reiatsu.
Despite his soul's pain and spiritual weakening, Tsunayashiro Tokinada tightened his grip.
"Everything ends. The world becomes dust… The Dead!"
He whispered the blade's release command.
In that instant, the space around him crumbled into swirling grey dust. Within the endless dust clouds, countless flickering souls appeared – the remnants of lives devoured by this sword across centuries.
Those slain by this Zanpakutō did not pass to hell, nor did they return to the flow of Reishi. Instead, their souls were forever enslaved, condemned to serve the blade's wielder for eternity.
It was a vile, accursed Zanpakutō.
Yet its power was undeniable.
That was why the Tsunayashiro clan guarded it so jealously through the ages.