In the last six hours of their fight, Kaguya gradually stopped haphazardly throwing big moves at him and their battle entered a more up and personal stage where Isshiki definitely held an advantage over Kaguya in the physical aspect.
Unlike her, he was experienced in hand-to-hand combat techniques, and now that he was aware of her disintegration bones, he took great care to avoid it.
But Kaguya had her own strengths.
For the n-th time, Isshiki tried to land a punch on Kaguya, only for a massive gravitational force to smash into him, staggering him and interrupting his attack, giving Kaguya enough time to get out of his range.
Isshiki inwardly cursed. This fight was beyond annoying for him. He was clearly physically stronger in all aspects except for physical endurance because of her bone armor. But he could not land a hit on her.
Creating a black rod, Isshiki pressed on and tried to follow up with his offensive, only for Kaguya to whip out her own black rod and clash with his, sending a shockwave throughout the surroundings.
They exchanged a quick flurry of attacks and parries before they finally took a distance from each other again when seeing it go nowhere.
"Aiming at my arms and legs? You won't be able to kill me like this." Isshiki expressionlessly said but inwardly he was slowly regaining his confidence. With most of his spatial abilities locked, he purposefully held back from using his second-best ability.
He didn't try to enlarge or minimize the objects and weapons around him during their clash, waiting for the best chance to strike a fatal blow.
"I don't need to kill you for you to die." Kaguya answered and chuckled at her logic but in this case, it was the truth.
Isshiki instantly understood that she knew and his expression grew grave.
Seeing his expression, Kaguya involuntarily chuckled again. Isshiki always thought her stupid. It was how she could get close enough to him to ambush him all those years ago. He was a very paranoid individual. There was no way she could have ambushed him like that if he considered her even a slight threat.
Alas, he didn't. He had always seen her as weak and dumb and that was his undoing.
"Did you really think I wouldn't notice?" Kaguya raised an eyebrow at Isshiki, not knowing if she should be amused or insulted. "The more I injure you, the more you are forced to heal, the quicker will the life force of your current vessel deteriorate. In the end, you will die anyway. It's just a question of time."
Isshiki narrowed his eyes, "I won't die." He flatly said.
It could be taken as a useless bravado and Isshiki probably wanted Kaguya to take it as such. After all, the truth was often the most unbelievable thing, but unfortunately for him, Rei made sure to share some intel about him. Intel even Kaguya was not aware of, despite their long-time co-operation.
"Ah, you mean the little technique that allowed you to survive my ambush all those years ago, huh? Kama, or whatever is its name?" Kaguya smugly asked, and this time, Isshiki's worry really showed on his face.
Kama was something he kept hidden at all costs. It was his way to be reborn and he never shared its real purpose with anyone so he had no idea how Kaguya could know about it.
While he was inwardly freaking out, Kaguya decided to mock him further. It was hard to get the ever-logical Isshiki out of his pace so she enjoyed having the upper hand for the moment.
"Well, how convenient that my partner had deployed spiritual restricting seals all over the place, no?" She innocently stated, knowing full well it would sound like a death sentence to Isshiki's ears.
Kama sounded like a mysterious and overpowered technique. The ability to cheat death and be reborn in a previously marked vessel after being killed... It was really special.
But just like Kaguya's Rinne-Sharringan's special ability could be for the most part made obsolete by Rei's simple spatial lock, her beloved's sealing arts had a perfect answer for Isshiki's technique too.
Apparently, Rei's research into the more spiritual aspect was not just a coincidence, and the fact he could grant Kaguya her meeting with her long-deceased foolish son was not the actual final goal, but rather just a nice side-effect.
Kama's description made it out to be some kind of wondrous ability where the user died in one place and could be reborn in a different vessel in another but nothing that seemed magical at first glance in this world was actually so simple.
Kama could make Isshiki's clone from his DNA but for his rebirth, his new vessel needed also his old soul. Upon his death, the Kama mark would drag his soul into the new vessel and the forceful takeover would be initiated.
But... what if Isshiki was trapped in a separate dimension and his soul was unable to leave it upon his death?
No. There would be no rebirth for him this time. Not on Rei's watch.
Hearing Kaguya talking about spiritual seals, Isshiki for the first time felt a cold sweat drench him as panic seeped into his usually calm mind.
He was fully aware of what this barrier would mean for him! His technique was not magic that somehow teleported his soul to a new vessel. Such a thing was impossible!
If he died inside a spiritual seal, his soul would not be able to get out and that was maybe even scarier than death itself to him. Death was something he feared but it was unknown. One can fear the unknown only so much.
Being aware that after his demise would come imprisonment and most likely him finding himself on the wrong side of the experimentation table... that made Isshiki feel a deep fear.
As his mind tried to find a solution to his predicament, he almost instantly remembered the man who accompanied Kaguya. The same man who first teleported them into this dimension and then disappeared.
Isshiki didn't put much importance on the man. It was just a human and compared to him, Kaguya seemed like the bigger threat. Isshiki didn't have the leisure to spare on some worthless ant.
He only now realized what a massive mistake that was.
The man was obviously a seal master and this 'partner' Kaguya was speaking about.
'I need to find and kill him or I will really be finished here!' Isshiki thought in dismay, and at that moment, his mind was made up.
Not bothering to pay more attention to Kaguya than strictly necessary, Isshiki spun on his heel and ran away from her under her baffled gaze. He had more important things to do than fight with her. Namely, he had one human that needed killing.
Kaguya watched Isshiki's retreating back with a mix of bewilderment, disbelief, and amusement. It didn't take a genius to realize what he wanted to do but...
'The idiot clearly didn't realize I am not the most dangerous person in this dimension.' She chuckled and shook her head.
For a moment, she considered attacking him since being ignored like this rubbed her the wrong way but then she remembered all the humiliation she suffered under Rei's seals and decided that Isshiki needed to be brought down a peg or ten.
No matter what she would have done to him could compare to how helpless Rei would make him feel with his seals.
With a smirk, she just watched the ignorant Isshiki willingly run to his own demise.