Last time in I was reborn in demon slayer as an Uchiha

Sanemi was pissed but before he said anything, Atoru said"But you guys have the advantage in numbers so throw away that samurai pride because today im going to teach you the art of jumping somebody"

As he said those words he summoned shadow clone and he said "each of those clones are weaker than you and I will show you how effective it is"

They lost pretty badly but after that he did healed them and he said "if you want it to be as efficient as possible you would need coordination and that why I'm making you guys fight against me with a partner"

Flashback end

Even though Sanemi would never admit it, Atoru method of teaching worked and it proven to be efficient.

He knew he couldn't beat that moon by himself and if he didn't have those class with Atoru he would be a lot more hurt right now.

'Fucking uchiha'was all Sanemi though as he attacked Kokoshibu.

Now we continue where we left off

Kokoshibu multiple eyes allow him to see what they were all doing and with those eyes, he was also able to see their chakra network.

They all had access to way more of their chakra then they should has access to but Kokoshibu didn't try and think too much about it.

Now all his focus is on separating them and killing them one by one.

That is the only way, he can see himself winning this fight.

If he tries to take them on right now he will lose, Kokoshibu decided to take out the heavy hitters first. 

He wanted to make sure that he murder or wounded anyone that may pose a threat to his life. 

He was not too keen on dying here, he also needed to take care of one of them because having four of them attack him at the same time, it a bit hard. 

Even though he had six eyes with two of them being a Sharingan, he could not keep up with so many opponents running at him at the same time.

Kokoshibu then created a huge moon slash that separated them.

Each of one of them were now too far away from the other to cooperate and he would make sure that it stayed that way.

The fight did not get that much easier for him after that, it became a lot more complicated than it needed to be, he now had to keep his eyes on 4 people at the same time and those four people were attacking him from random direction and at random times.

He also had to make sure they do not get close to each other or he might be on the receiving end of some harsh beating.

As they were fighting and breaking thing all around them and just created less and less place that the pillar could use to hide or sneak attack the upper moon, the battle field was full of battle mark.

While this was happening somewhere else in the castle Obanai, Giyu and sabito were having there own fight against upper moon six.

Anyone of them could individually kill that upper moon in a millisecond, but the demon blood demon art was very annoying and it had a lot of uses.

This whole castle was her blood demon art and because of that she has control over this whole place.

She can make walls appeared and disappeared out of nowhere, she can move objects and can teleport them to another room using her blood demon art.

And because she got a lot of blood from Muzan her ability got stronger, she was a pale woman with a grayish complexion, who had sharp, blue-stained nails and notably red lips which sharply contrasted the tone of her skin. She had shiny, waist-length hair of a dark brown color, which she wore falling down her back in slight waves that cut off sharply at the ends, with two chin-length strands left to frame her face and long bangs that obscured her large eye set in between them, swept to either side of her nose.

She wore a plain black kimono with a white lining, secured with a striped pale brown-striped obi, white socks and no shoes. She was always seen holding a four-stringed wooden biwa with a large bachi pick.

And it seemed like her power activate every time she played the biwa.

She had her hair to the side to expose that she possessed a single large, pink-colored eye with the kanji for "six" etched onto its iris. The upper portion of her face was also revealed, and appeared to be a darker gray color than the rest of her skin with prominent veins surrounding her one eye.

She was pain in the ass and it was really hard to handle her, anything any of them got anywhere close to her, she would manipulate the castle in a way that make them miss her or make their attack miss.

She also sometimes made the floor below them vanish making them lose their footing but they never fell for long as another one would come and save them.

So even if she was weak, if they did not pay attention to her and make this fight seriously they would die.

They knew it, death would be awaiting them if they messed up at least once.

Obanai with his servant breathing was able to wriggle his way around most of her attempts to his life like a snake.

While Sabito and Giyu moved fluidly like water, they looked homeless and shapeless and seem to adapt to any new situation just like water take the form of anything it is put inside of.

Nakime eyes made sure that she could see everything without missing a single detail so as long as this fight stay like this she will eventually wear them down and killed them.

They need to find a way to trick her and unlike in canon they don't have Yuchiro to make illusion for them so this is going to be a lot harder.(A/N she is a lot stronger either way so does it matter)

A/N I would be interested in any way you can see them use to trick her