Mystic Demon Slayer

Following that they just talked for a bit before everyone just went to do his own thing, seeing this he decided to rest for a bit and emulate the fight with kokushibo in his head

Half an hour later footsteps could be heard coming towards the room zenitsu is staying in, a couple of long seconds later the door opened slowly as a man accompanied by 2 little girls entered

He has light skin and black shoulder-length hair with a huge birthmark on his face he could be seen wearing a black kimono with a long white kimono jacket with a pink and purple mist like pattern that starts around the lower back/waist

As soon as he entered the man seemed to pause for a second before smiling happily as he looked at zenitsu and spoke with a voice that seemed gentle and fluid but charismatic at the same time causing Zenitsu to listen to what he is saying with more attention than he usually would

"Hello my child, my name is Kagaya Ubuyashiki and I am the leader of the Demon Slaying Corps"

Hearing this even the calm Zenitsu was shocked as he felt no power from the guy in front of him

'Is he lying? No probably not he has no reason to? Master never said anything about this… let's see what he has to say'

As Zenitsu was thinking the man in front of him did the same as he couldn't hold the excitement he is currently feeling

'I Can feel it… my instinct is telling me he is the most dangerous being I have ever met… he can also kill kibutsuji muzan!! that's what it is telling me...'

{A/N: Before you start typing your comment about how this is weird let me tell you that Kagaya Ubuyashiki has the ability of 'Foresight' do check it out on wiki}

After a moment of silence, Kagaya Ubuyashiki started talking again

"What do you think about becoming a Hashira?"

"Didn't I need to kill a moon demon to become one?"

"That rule is made so you have to prove your power, you weren't allowed before because there was no proof… but now it is different... So, my child will you become the thunder pillar of the demon hunter corps?"

"Lightning Pillar… not thunder"

Hearing this Kagaya Ubuyashiki Smiled and nodded to him acknowledging it and with that, he nodded and said

"It will be announced after your recovery to prevent any mishaps as I feel like someone will disagree.."

And with that, he said his goodbye and left with grace

'This guy is interesting… for him to hold the position without any power is even more so… ill think about it later I had to focus on recovering'

And so zenitsu closed his eyes to rest but he kept on replaying the fight on his head and how he could have done better with 'Zero Breathing: Strengthen' activated as usual but with higher efficiency to prevent his body from 'sleeping' with all the time he will stay in bed

* * *

And with that 2 weeks passed in the blink of an eye as he recovered a great deal which left the doctor surprised, but he didn't waste the time just there in bed doing nothing as he kept on replaying the battle in his head and now that he can already move again he can finally train

Standing in the garden under a tree Zenitsu moved slowly as he waving his sword around, slashing sometimes and thrusting others in a mysterious pattern

As he got faster and faster lightning started appearing around him as it crackled around scorching the ground but he kept on getting faster and faster while disappearing sometimes in a burst of golden lightning and appearing close by

It appears he is doing the same thing over and over again but if one could follow his movements they would notice him changing them a bit every time and perfecting them, And like that he kept doing so for 2 more weeks

* * *

By the time 2Months passed Zenitsu was fully healed and improved his swordsman reached a new level as he could feel a bottleneck which in the case he breaks through he will reach an unprecedented level of strength

And he also came to know how kokushibo was able to dodge him after he talked to the Stone pillar Gyomei Himejima and it is called the See-Through World he also told him how it works but even then he couldn't enter it so he may need more time to reach it… if he ever could

Also, the most noticeable change in Zenitsu in those 2months and the biggest boost to his power is the Demon Hunters Mark which he found its existence after replaying the fight for hundreds of times and finding something weird about it which is the extra boost he received after using the 'Forbidden Style'

And with a lot of trial and error, he was finally able to use it but the conditions were… hard to say the least as only after training to death and not giving up as he heart rate went over 200 bpm and his body hear went over 39 degrees and he was barely able to survive it

But following that as if passing some sort of test he became able to manifest it more easily as he trained in doing so

Zenitsu doesn't know if his Mark is unique to him but he remembered seeing kokushibo possessing a similar mark but in a different look

He still doesn't know if each one gives different power but his own seemed to get boosted by the concepts of lightning and death in his soul

As when he manifests it the use of concepts become way easier and even boosts their strength like the Mystic eyes of death perception and it also augments his physical and tactical abilities it also removed the curse that should kill him at the age of 25, But using it lowers his stamina a bit but it's manageable

And like that 2 Months passed since he entered the demon hunters HQ