Having received inspiration from the spar with his mistress, Shiki got to work in the privacy of his own personal training ground, assigned to him by Mito.
"Although I'm significantly stronger, because that increase was very well rounded, the places where I fall short are still pretty much the same." The boy thought out loud.
"I'm missing raw attack power and endurance. I have stamina and can take more damage than before but like for most shinobi, the lack of hard defense is still an issue I have to contend with."
"I also need to improve my ability to deal a lot of damage over a wide area. The Shuriken Shadow Clone Jutsu is very efficient but it's too lacking in power for my taste."
"I could upgrade my Assault Storage Seal or maybe find a way to expedite the growth of my elemental jutsu."
Having finished sounding out the areas he needed to work on, Shiki felt he had his work cut out for him.
All there was to do now, was set priorities and get started.
And since self preservation was the priority both himself and Mito decided on, after some further thought, the first issue to address became clear.
Even if one lacked the power to outright defeat an enemy, there were still various options one could take depending on the situation.
Looking for an opening to escape with superior speed was a very viable option for someone as fast as Shiki.
Using his nearly endless stamina due to being able to metabolize nature energy and turning the battle into one of attrition or just stalling until allies could arrive was also possible.
All those strategies required was for the ability to stay in the fight long enough for them to be implemented.
As such, endurance, specifically toughness and rapid recovery were the aspects the boy felt he should home in on first.
With that in mind, Shiki revived an idea that he had previously dismissed.
You see, like many reincarnation, the boy felt like attempting to recreate techniques from other anime he knew, just like his attempt at mimicking the Breathing Techniques from Demon Slayer leading to the creation of the Three Bodies Breathing Method.
One such technique was Blut from the Bleach series.
However, he had wisely researched various medical documents and chakra studies in Mito's library before making an attempt which led him to conclude it was impossible.
Blut involves flowing energy through the bloodstream and there is a reason people in the naruto world have a separate chakra circulatory system.
Flowing chakra through one's body is one thing but attempting to do so through something as delicate as one's blood vessels is simply not a good idea.
Not to mention pointless as directly focusing chakra on body parts as a whole would be a much more direct and efficient way of strengthening them.
So that idea was scrapped before Shiki gave it any real thought.
Now though, with his new Ryumon physiology, there were new considerations to be made.
The Art of the Dragon Blood was a Ryumon Secret Technique for flowing metabolized nature energy through one's blood to distribute it across the body. It served as a foundation technique that allowed Hollows to switch between its mutually exclusive advanced forms.
These three being the Art of the Dragon's Scales, Art of the Dragon's Force and Art of the Dragon's Life, their purpose being body hardening, strength enhancement and increased healing respectively and only one could be active at a time initially.
As such, Shiki believed his new Void Chakra might allow him to use enhanced versions of these secret techniques which his incomplete self had used against Kumo in their original chakraless forms.
'All right then, let's start slow, with a small and steady stream of chakra.' The boy mused and began his experiment.
Much like he expected, the void chakra melded into his bloodstream and flowed through his entire body harmoniously though there was no noticeable change to his physical abilities, likely due to the small amount of chakra being supplied.
'So far so good.' Shiki thought.
'Let's try to slowly raise the chakra output until the situation changes.' He decided to continue.
Proportional to the increasing supply of chakra, the boy's blood flow began to accelerate but the chakra also strengthened his blood vessels, enabling them to withstand the rising blood pressure.
This was the equivalent of the basic Art of the Dragon Blood, a moderate but stable overall boost to the user's abilities.
'The chakra drain is noticeable but plenty manageable.' Shiki noted.
'The increase in my overall physical abilities, toughness and recovery are definitely worth it.' He concluded, ceasing his active supply of chakra to his bloodstream.
Much to his shock however, the drain did not stop.
The cycle, though needing his input to start, now ran by itself and automatically molded more void chakra from his spiritual and physical energies to sustain itself at the same rate the boy had previously set.
As a knee jerk reaction to having his chakra drained involuntarily, Shiki forcefully cut off the flow which made the chakra in his bloodstream go berserk and popped several of his blood vessels in the process, resulting in severe pain and internal bleeding.
Still, pain and injury are but a casual thing for Hollows of the Ryumon clan so the boy hardly paid them any heed.
Exploring the characteristics of this new Nirvana Art he was trying to develop based on the Ryumon clan's Art of the Dragon Blood was a matter of far greater importance.
'Right then. Let's try it again, this time being a bit more deliberate.' Shiki decided.
The boy then slowly began flowing void chakra into his bloodstream until it began cycling, before stopping without raining the supply too much.
The flow then died out normally, the previous phenomena of self continuation not manifesting.
'Maybe I need to raise the cycling to a certain speed and chakra drain level before it can run by itself?' Shiki theorized.
He then resumed his experimenting and after a couple more runs and a few hours of theory crafting, he had more or less figured out how things worked.
First, Shiki needed to supply enough chakra to manually jump start the cycle which only occurred after it reached a certain speed.
Second, whatever rate of chakra drain the boy manually stopped at became the autonomous drain rate though he could adjust it up or down afterwards.
Third, to stop the cycle, it had to be done manually or it would continue until all his chakra was burned and he died, a rather chilling property of the jutsu.
Fourth, if Shiki wanted to stop the cycle without injuring himself then he had to progressively lower the chakra supply because forcefully stopping it dead once it was up to speed just made the chakra burst out randomly, resulting in various internal injuries.
'Alright then, finally got a handle on the new and improved Art of the Dragon Blood. Now I just have to figure out how to activate the advanced versions, should be easy enough with the foundation all figured out.' The boy thought to himself.
As it turned out . . . Shiki was wrong.
+++++
Hey, Author here!
Just a reminder that you can read up to a FULL MONTH ahead of this site on pa-treon.
I'm trying to become a full time Author now and I'm not going to be starting any new novels just so I can make sure this one is properly completed.
Find those sweet advanced chapters on pa-treon.com/lusoba without the -