The battle between Yoriichi and Muzan was
epic, or more like a single sided spanking by Yoriichi. Whatever the case may be, this encounter has
had Muzan pissing his pants for centuries. But, what if all this never happened? What if, Muzan and Yoriichi worked together? Will Yoriichi ignore his morals for Muzan? Let’s find out! It’s the Sengoku period, and the Tsugikuni
household is blessed with twins. But, the priest of the family considers it
a bad omen and informs his master, who proceeds to kill one of the twins with a weird birth
mark on his head. But, the twin’s mother protests, keeping
her life on the line, and they come to a treaty where the father spares the life of the other
child but orders him to leave for a temple to become a priest once he is old enough. The boy grows up, seemingly deaf from birth,
garnering the pity of his mother and older twin brother. But one day, the same boy picks up a sword
for the first time and strikes down a seasoned swordsman multiple times, at a misguided attempt
to answer his calling. This boy is none other than Yoriichi himself. Years pass, and Yoriichi finally departs for
the temple after his mother’s death. The sun sets, and along the way, Yoriichi
encounters a strange man beside the road. He slowly treads towards the man and realizes
that he’s no man, but a demon. Yoriichi gets petrified, and the bag holding
all his belongings hits the floor as Yoriichi goes for a rock nearby. The demon leaves the man and attacks Yoriichi
instead; however, Yoriichi throws the rock at the demon’s foot with all his might,
making the demon tumble. The demon tries to crawl towards his name,
while continuously muttering the name of a woman. Suddenly, a swordsman appears out of the bushes
and beheads the demon. The swordsman explains that the poor man’s
soul must be suffering, due to resisting the transformation, as he still had memories from
his human life. As the demon starts turning into ashes, Yoriichi
lets out a prayer, just like his mother, to the sun god, asking him to forgive the man. This was Yoriichi’s first encounter with
a demon, however, his heart bore no hatred towards them, rather, a sense of deep pity
and remorse. The swordsman turns to walk away, instructing
the boy to stay indoors during the night, but the blank eyes of Yoriichi stare right
through the swordsman’s chest, making him a bit uncomfortable. As the swordsman, a.k.a. the demon slayer, starts walking, Yoriichi
declares that the man must get his chest checked by a healer, as he’s suffered multiple fractures
in his ribs. The swordsman turns back in awe, and asks
the kid how he knows that, knowing full well that he was hit there earlier while chasing
the demon. Yoriichi replies earnestly, that he could
see through objects and human beings. The Slayer is shocked, and further inquires
if that is the reason why the boy chose to trip the demon rather than fight him? Yoriichi, replies in a plain yes. The slayer further inquires about Yoriichi’s
past and, knowing full well that he has no one to look after him, takes Yoriichi under
his wing as his apprentice. This slayer is revealed to be Renjuro Rengoku,
an ancestor of the Rengoku family, with the same perky hair. Renjuro takes him to the then demon slayer
corps headquarters, and introduces him to the other demon slayers. Renjuro then goes on to explain the importance
of his job to Yoriichi, and how the world would be overrun by demons if the slayers
weren’t there to protect the people. Yoriichi is quiet as usual, but he clearly
sees a horde of people behind the paper walls talking about his sudden appearance. The other demon slayers are still hesitant
to accept the young prodigy, however, Renjuro has his utmost faith in him. Years pass, and Yoriichi grows up in the Rengoku
household, developing his sun breathing like in the original story and passing it onto
the fellow slayers, who adapt to it in their own elemental ways. Soon, the time for Yoriichi’s first mission
arrives, and he is sent to a town far away, where a demon is supposedly coordinating his
attacks to kill wealthy people. Yoriichi, reaches the town and realizes that
it’s the same place where he grew up. Suddenly, the convoy of a rich landlord arrives
at the scene, and Yoriichi senses a null demon presence. He looks around with his transparent vision
and notices that the demon is himself in the crowd. As Yoriichi notices the demon, it rushes towards
the man sitting in the hand-held carriage in order to kill him, however, Yoriichi cuts
him down immediately. As the carriage falls over, it is revealed
that the wealthy man traveling in it was none other than Michikatsu, Yoriichi’s brother. Michikatsu looks up at his forsaken brother
with a frown of awe and disappointment as he sheathes his sword. Later, Yoriichi explains his condition to
Michikatsu, and upon hearing that, he decides to leave his family behind and learn the breaths
to become a demon slayer himself. Michikatsu too joins the demon slayer corps,
however, he is unable to learn the breath of the sun and hence has to rely on using
a mock breathing technique, known as the breath of the moon. Time passes, and the brothers are dispatched
to take care of a situation in a nearby town, where multiple killings by a ghost like identity
were reported by the locals. The brothers reach the location and encounter
the ghost, which is a demon, as they suspected. Moments before the Tsugikuni brothers unsheathe
their swords and rush in to kill the demon, he cries for help. This throws off both brothers as they try
to contemplate the situation in their minds. The demon cries out loud, explaining that
he isn’t doing this by choice and that he is actually being controlled by an even more
ferocious man, the one who turned him into a demon. Yoriichi uses his transparent world to take
a look at the man’s insides and notices a below average physique with no power to
boast. Yoriichi decides to hunt for the stronger
demon, believing him to be the progenitor of demons, while Michikatsu stays behind to
slay the demon in case he is lying to escape. Yoriichi reaches the specified location at
a shrine, tries to use his transparent world ability, however, the foul stench of a certain
incense and the pitch-black darkness hinder his attempts. Suddenly, an unknown being rushes towards
Yoriichi, and he cuts it down immediately. As Yoriichi’s eyes adjust to the darkness,
he witnesses a horror like none other. Yoriichi realizes that the unknown thing he
cut down was actually a human hostage that the demon was saving for later. In an absolutely vexed state, Yorrichi rushes
back to Michikatsu, fearing for his life. As he reaches the spot, he finds it to be
empty, but suddenly a severed hand [like Enmu’s] reveals itself and talks to Yoriichi. The hand reveals that the demon they spared
earlier was none other than Muzan himself, who altered his body’s chemistry to look
like that of a low-level demon. Muzan knew about Yoriichi’s capabilities
right from the day he met Renjuro and killed the demon he created. The hand lays down the conditions for Yorichii
as follows: If he wants to see his brother alive and well, he must get him the head of
the Oyakata-sama of the demon slayers within a week at the same shrine he cut down the
innocent human. Yorichii dashes towards the hand, however,
it vanishes into thin air even before Yoriichi could land a single blow. Torn between his duty and his love for Michikatsu,
Yoriichi reaches the headquarters of the demon slayers. He meets Renjuro and sits in front of him,
uttering no words for several minutes. Renjuro gets worried and asks him what actually
transpired during the mission and where Michikatsu is. Yoriichi retells everything that happened
during the mission, which makes Renjuro really concerned. Renjuro gets up and declares that it's time
he finally met the leader. Yoriichi looks at Renjuro with a concerned
look as he follows him. They sit down and wait for the leader to appear,
however, after waiting for several minutes, a timid boy, no older than 4 years, appears
hanging onto his mother’s clothes. Yoriichi, is shocked to find out that the
leader passed away at the age of 23, leaving behind his only son, and that all the members
of the Ubuyashiki household suffer from a horrible curse that makes their lives regrettably
short and painful to live through. Renjuro, however, gets up and grabs his sword. Suddenly, he unsheathes his sword and impales
himself in an act of seppuku. Yoriichi is shocked and immediately rushes
to Renjuro’s aid. Renjuro explains that he was the one who dragged
an ignorant child into this painful world, and that this is the only thing he could give
in return to Yoriichi as atonement for his brother’s capture. He then goes on to explain that he must take
his head instead of the young master’s to free his brother, as he slumbers in eternal
sleep due to blood loss. Yoriichi lets out a tear as the man who was
no less than a father to him dies in his arms, due to a mistake he made. Yoriichi reaches the same shrine after a week,
only to find no one there, Suddenly, a voice echoes in the halls, stating that his brother
would be released after he rolls the head of the leader towards the statue of Buddha. As soon as Yoriichi rolls the head wrapped
in a cloth towards the statue, strikes of distorted air hit the bag, revealing that
it’s just a bunch of rolled up clothes. Yoriichi grabs his sword and takes a fighting
pose, stating that the demon will meet his end tonight. Suddenly, a few strikes are let loose from
right behind Yoriichi, which he easily dodges, but as soon as Yorrichi turns and identifies
the man behind those strikes, he goes into a state of shock. The ambusher turns out to be none other than
Michikatsu, his brother, who’s been turned into a demon. Yoriichi, in a concerned voice, asks for Muzan
to show himself, as the former declares that Muzan will die for what he did to his brother. But as Yoriichi stops, Michikatsu, slowly
utters: "Michikatsu was my human name, call me Kokushibo." A frown of worry climbs up Yoriichi's face
as he takes another look at his brother. Kokushibo then goes on to state that Muzan
has nothing to do with this, and that he’s accepted the life of a demon of his own accord. Kokushibo explains that the moment he saw
him again that night, slaying the demon, he knew that he’d never be enough. Never be capable of standing shoulder to shoulder
with his brother. Never be enough to be his equal. That’s why, when he was approached by Muzan
months ago, he accepted his offer to become a demon, as he was going to die anyway after
the age of 25 due to the demon slayer mark. Yoriichi’s life flashes before his eyes
as he recalls all the moments spent fighting alongside his brother. But as he clears his mind and dashes towards
Kokushibo to kill him, a whip like thing almost hits him in the ankle, but he manages to avoid
it at the last moment. Muzan, too, reveals himself as the two demons
prepare to take down Yoriichi for good.
