The Harshest Sea
Within the Royal Palace, Oetsu and his assistants stood outside the Hooden, staring at a grand black block of stone, covered with chains, ice and wacky mechanisms that served to prevent the vault from being opened.
"All right, it's time ladies!" Let's get this show on the road." Oetsu ominously exclaimed before fire works went off around them, making Mera face palm at the the ridiculous antics that Oetsu would go to for any little thing.
"First up! The lovely Hairy Hasuka Hashihara!" Oetsu shouted, standing with pride as he put his hands up in I love you gestures as his puffer jacket blew in the wind. Extending her hair into different strands, its internal bonds strengthening as she grabbed on to the chains and ripped them apart, casually discarding them on the ground. These chains were special as their integrity was based on the chains working in tandem; if one was broken, it could be repaired instantly before another one was broken meaning all chains had to be broken at once; a feat few could manage.
"Step two: The Fiery Mera Hiuchigashima!" Oetsu yelled, drastically shifting his position, rapidly lifting his hands as he holds them in gun like poses, firing off randomly in the direction of the stone while Mera reluctantly spew dense flames that melted the ice. Unlike the flames of Engetsu, Ryujin Jakka or other flame type-zanpakuto, the ice that formed could only melt at a specific temperature, a degree to which only Mera could perform.
"Step three: The Adorable Nonomi Nomino!" Oetsu shouted, changing his pose again to something goofy that made one question how flexible he was. With the ice melted, all that was left was a raw block of stone. However, as Nonomi's hands turned into chisel and she began to chip at the stone, they finally saw the real thing hidden within the stone - a vault. Where one not to be careful, it would be easy to break the mechanisms of the first door and destroy the mechanisms that were responsible for opening the door; requiring the finesse of someone like Nonomi.
"Step four: The Vibrant Tokie Tonokawa!" Oetsu roared, shifting his pose again to now be dabbing, looking less cool than he thought he did. Looking at the first door of the vault, it was apparent there were some water based mechanisms that required different concentrations of water in different locations, along with it being able to maneuver in a way that seemed to defy gravity too to be able to open the door. Able to freely manipulate her tears, Tokie sent water from her eyes to the door, filling in the mechanisms as required, soon after opening the door.
"And now the final step: Go Forth Great Tsumiko Tsuchimiya!" Oetsu called at the top of his lungs, randomly sitting now with great aprehnsion, like a kid during story time. He watched with great excitement as she pulled multiple teeth and reshaped them to keys, being the only one who could make the keys required to open the final door of the vault. As the final door opened, Oetsu finally got up, embracing what lied dormant on the other side for thousands of years.
"At last, we're reconnected... My zanpakuto." Oetsu calmly uttered, claiming the zanpakuto then closing the door behind him. The others looked upon in surprise as the zanpakuto was completely different from what they expected, instead of a regular blade, his zanpakuto resembled that of a golden blacksmith's hammer and being zanpakuto spirits themselves, they all felt a certain uneasiness around it.
"Alright, you lot behave while I'm gone." The royal guard ordered.
"Wait, how are you planning to get down, it'll take ages to go down the normal route and the others left the pillar down there with them to return." Nonomi asked.
"Oh don't worry, I'll be down there in just a few minutes." Oetsu said, before raising his arm with his zanpakuto in it before swiftly aiming it downwards and within a split second crashing through the ground, leaving a huge hole in the ground to the annoyance of Mera. Before they could even tell, their boss' reiatsu was far away from the royal palace and he would soon be in the seireitei...
In the midst of the battle between Tenjiro and Reiō, the royal guard continued to try directing waves of harmful water towards the divine entity, but each time the water would just pass over him without dealing any damage. Tenjiro didn't fully understand why but he kept at it, aiming to stall as long as possible, swinging his zanpakuto to control the water's motion.
"If this isn't gonna work, I guess I'll have to put in a bit more effort, eh Reiō?" Tenjiro tauntingly exclaimed, the soul king unbothered. Tenjiro exerted his reiatsu before using his zanpakuto properply: "Flash, Kinpika!" For a split second the soul king was blinded, even taken aback from the blinding light that seemed to reflect off Kinpika's blade, and before he could react to what Tenjiro had planned, the royal guard delivered a direct blow to the soul king; the waves of water flowing in a circular motion around them as Tenjiro flash-stepped before the soul king.
"Hmm... Looks like I can hit you after all." Tenjiro gloated even after seeing Reiō's body regenerate almost instantly as he flash-stepped to gain distance.
The royal guard swung his zanpakuto again in a circular motion where he stood, ready to attack again before Reiō decided to go on the offensive against him. Suddenly, he planted his zanpakuto to the ground, the blade planted first, as he remarked to himself how it was a good thing the barrier was so wide. The water that surrounded them faded too, as Tenjiro called out: "Bankai: Sokonashi-numa no ketsuyoku (Bloodbath in the Bottomless Swamp). Water poured out the the top side of his zanpakuto, quickly filling the area around both of them until they were emerged in a deep sea that seemed endless in depth. "Now the real fight begins..." Tenjiro warned arrogantly.
As the soul king looked around, taking in the separate space they seemed to have entered, distant from the outside world, Tenjiro stated: "Yeah, it's just the two of us now, and unfortunately this place is quite the dangerous sea." Where the two seemed to have gone into a separate dimension filled with water, the real danger was not in some odd creatures floating within the water but rather the water itself. With each passing second, the water around them was leeching off their reiatsu and draining them. Thanks to the royal guard's intense training in order to master his bankai, he had managed to strengthen himself within the harsh conditions to decrease the rate at which his reiatsu was lost. The average captain would begin to lose consciousness within just seconds to a couple minutes of being in Tenjiro's bankai, and the only way to escape or leave this world was for Tenjiro to recall his bankai or him die first; a weakness he worked vigorously for that never to be the case. Due to the quick rate at which reiatsu was stolen, it was best for any opponent to conserve their reiatsu as best as possible and reduce motion if they wanted to stand a chance to survive. Tenjiro intended to use this space to weaken the soul king enough to deal serious harm, hoping his regeneration would be slower as well. Travelling at speeds faster than shunko or bringer light could achieve, he intended to circle around the soul king and attack with haste. However, this seemed futile as the soul king was able to react each strike and avoid taking damage for minutes.
"Damn... I thought without him having all the fragments, I'd at least stand a chance at hitting him in here but it's like he's not even being slowed down." Tenjiro remarked, starting to exhaust himself. The royal guard began to observe the soul king more attentively, soon after receiving a shock as he realized the water was circumventing his body. He was left aghast as he acknowledged that the soul king's power was so great that he continuously was subconsciously manipulating the space around him to avoid the water touching the surface of his skin. However, the big problem was that by not touching the surface, the water couldn't seep through the skin which was where most of the damage was done. Once the blood water was under the skin, it could massively affect the internal structure of an organism, disrupting blood flow by causing blood clots and erosion of red and white blood cells, as well the walls of the organs and muscles from within. Starting to reach his limit, the royal guard realized even he was out of his mind trying to go toe-to-toe with the soul king and recalled his bankai.
"Well that was pointless.." Tenjiro remarked, lost as to what he could do now, left exhausted.
"You shinigami... always interfering...I guess I have to purge you lot first." Reiō stated, alarming the royal guard as he closed his eyes and put his hands together in a praying form, before a sudden burst of darkness emerged from him and began to engulf all of the seireitei. In that moment, even the captain and the other guards began to look distressed, wondering what the soul king was about to do.
"He's using Aizen's bankai." Ichibe exclaimed.
"Wait.. all this time he was able to use Aizen's zanpakuto abilities as well. I thought once he took over, that part of Aizen would be lost. Why did we need to stop him from getting the almighty if he already had this available to him?" Senjumaru shouted in a frantic state.
"Relax... you really need to trust in me more." Ichibe responded.
As the radius of the bankai expanded more and more, expected to cross even outside the seireitei and cover the whole of soul society, with a sudden strike it was shattered completely. As the soul king opened his eyes to identify what had just stopped him, he looked up to see Oetsu with a grin on his face.
"No unauthorized bankais on my watch!" He gloated...