Whenever a few swordsmen first meet, Kokushibo instantaneously reiliar to help you your.  Just after informing Kokushibo his label, Muichiro is actually surprised as he was informed that he’s a descendant from Kokushibo’s. However, they can overcome their fear and you can assault Kokushibo however, is readily simple. Kokushibo openly says one Muichiro is rolling out swordsmanship for an individual his ages that’s happy to the stage in which he’ll transfer your with the a demon so you’re able to suffice Muzan. 
Due to the fact battle between Kokushibo plus the Devil Slayers concerns a finish, Muichiro may be able to come to an almost proximity so you can your and is able to pierce your together with his transformed red-colored katana, briefly immobilizing your. Although not, Kokushibo continues to struck and you can fatally wounds Muichiro. Whenever their battle ends Echo-Dating Kokushibo displays his guilt during the having hit down his descendants. 
When he very first satisfied brand new Stone Hashira, Kokushibo marvelled during the their real overall performance, saying it had been 300 many years since he past watched anyone off Gyomei’s quality. Once a first conflict, Gyomei is actually forced to fool around with his Devil Slayer Marks to the newest play ground. Kokushibo pitied your getting wasting his lifetime and electricity simply to die, detailing that at night chronilogical age of 25, he had been condemned so you’re able to pass away in the future. Gyomei denies so it statement and suddenly taunts Kokushibo by saying some one designated and you will above twenty five years of age got stayed in the fresh new previous. Kokushibo after that episodes your with restored ferocity immediately after remembering his hated sis.
Remembering Yoriichi’s terminology one a generation tend to surpass their currently powerful point in time from Demon Slayers, Kokushibo turned scornful of your Hashiras attacking. In particular, he teased Gyomei since the unnatural, to own surpassing the new constraints of human beings and you may reaching a growth within the stamina particularly demons. Sooner, Gyomei and you will Sanemi are able to behead Kokushibo. Even after regrowing a special head, Kokushibo’s healing eliminated away from attacking his humankind, enabling the fresh new Stone Hashira so you’re able to decapitate once again, this time around, causing their passing.
Kokushibo basic came across Muzan as he got has just discovered that his Devil Slayer Marks would lead to him in order to perish on an early on age. Muzan, trying to find a demon exactly who made use of Breathing Style, provided him a chance to real time and start to become more powerful permanently. Bringing the promote, the guy changed into a devil, used a unique identity and finally achieved the new rank away from Upper Just one of their 12 Kizuki. Kokushibo are dedicated so you’re able to Muzan, becoming enforcer towards Several Kizuki.
In return, Muzan observes your since a corporate spouse,  you can easily on account of their enthusiast commitment so you can him, becoming his strongest Demon and since the two was indeed as one responsible for pretty much exterminating Sunshine Respiration. Despite this, Muzan carry out nevertheless admonishes him with the rest of your own Higher Ranks, because of their failure to obtain the Bluish Crawl Lily and never eliminating the latest Ubuyashikis. Kokushibo don’t retort their report and simply claimed the Ubuyashikis provides hidden on their own away from have a look at.
You will find hostility between Kokushibo and you will Akaza. He doesn’t get plus Akaza, because the he notices him because an excellent weakling just who disrespects Kizuki exactly who is actually regarding a top ranks than just him. This will be shown the very first time when he scolds your having wanting to initiate a struggle with Doma, and soon after with the as he calls your „extremely poor“ for not wanting to save fighting up against Giyu Tomioka and Tanjiro Kamado. However, despite the reality he does not get together with Akaza, Kokushibo later on shows acknowledgement into the your once learning one to Akaza try nearly able to regenerate their head, hence drives Kokushibo to try the same.