yandere!poseidon headcanons with fem!kokushibo!reader
warning: obsessive behavior, violence, spoilers from manga/anime. Please take caution when reading the content.
Credit for this piece goes to @recreationalfanfics and their phenomenal works, specifically this one. I would like to specially thank my friend @nixes-noxes for helping me fine-tune this script to its fullest potential.
The intention of this story is for entertainment purposes only. The behavior exhibited here is inappropriate and unhealthy, hence it should not be encouraged. There are also triggers, so please take caution. You are responsible for your Internet consumption!
A demon was born from the malice of mankind. That is the story that humans and gods believe…but that is not the truth in your case.
Fearing death, you willingly drank Muzan Kibitsuji’s blood and became the first Upper Moon. One of Twelve Kizuki to serve him and provide aid in his quest to obtain a solution to walk in the sunlight. You had died by the hands of your descendant and his fellow Demon Slayers, unsatisfied with the life you had lived as an abomination. In the end, you could not attain the innate talent your little brother possessed.
Because you were a creature classified as ‘evil’, you were confined to the depths of Helheim as punishment to suffer for all eternity. Not wanting to perish for a second time, you sliced down enemies and cultivated your Moon Breathing Style in the hellish landscape before you were suddenly plucked out of that place, coming face-to-face with your new master: the Valkyrie called Brunhilde.
Apparently, she had intended to call out another champion to fight against the gods in a tournament known as Ragnarok, but for some unknown reason you were whisked here by her summons. Seeing this ‘accident’ as an opportunity, you laid out your sword and offered your loyalty to her. Yes you were a demon, but you had been loyal to Muzan until your dying breath. Being the servant to a demigod would not be any different, minus facing the antagonization of both human and gods alike for just being by her side.
It was better than returning to Helheim, anyway. The water did not scorch your skin and the high quality tea leaves were exceptional.
The smallest pleasures in life made a difference…but does that include being on the roster to fight against the infamous tyrant of the divine waters, Poseidon? Probably not.
Yandere!Poseidon
This is a god who is the physical embodiment of perfection. He is a king who has no need to be supported by individuals who are beneath him in the hierarchy of all life. Furthermore, he was not pleased when his little brother had added him as a contender in this childish tournament without his consent. Why stall the inevitable fate of humanity with Ragnarok? It’s honestly a waste of time for him.
There has never been an opponent who did not quiver at the sight of his trident nor survived to tell the tale. So why should he even bother to give any effort in this fight? His opponent was a demon. It is only natural that a demon would be stomped down by someone like himself, even if it is a female one with a slightly impressive physique and once bore the moniker ‘Moon Hashira’.
Untamed [Hair Color] tresses held together in a ponytail that reached to her waist. [Favorite Color] nagagi-kimono and black umanori-styled pants tied with a white obi. [Eye Color] irises and red sclera with words written on them.
The only reason he even recognized the clothing is because Aphrodite whined about the ‘poor fashion’ taste of Brunhilde’s new ‘pet’...but did she honestly expect anything more from a demon?
No, but she enjoyed hearing the others praise her intellect and how no one could ever hold a candle to the beauty of the lusty goddess. A hypocrite by any other name. She and Ares had another falling out, again.
Still it would not bother the gods nor himself by allowing his opponent to try and land a hit on him before killing the unfortunate abomination. The effort of an ant trying to avoid being crushed by a boot is always…adorable.
This act of ‘kindness’ towards the Moon Hashira led Poseidon into a match that has lasted longer than the previous Ragnarok bouts. She did not hesitate to use the water surrounding the arena to create a heavy mist that acted as a smokescreen before attacking from behind with her sword. She slashed his calves and right forearm, then jammed her sword that is made from her own flesh and blood into his stomach. She was going to kill him. She would do whatever it took to win the fight.
This revelation enraged Poseidon. How dare a demon think that she can kill a god? Blasphemy! HE IS A GOD, HE IS PERFECTION. ANYONE WHO DISAGREES HIM DESERVES TO DIE.
And yet he still found himself kneeling on the circular platform, leaning heavily against his trident with the bloodied edge of her sword pressed against the side of his neck. If it isn’t the reversal of positions that bothered him the most, it was the look of indifference dancing in the Moon Hashira’s eyes. As if he was the one being a nuisance and not the other way around.
Suddenly, she withdrew her sword and sheathed it. “I will not kill you.” She said, “A hierarchy exists to keep the balance between those who sit at the top of the food chain and those who are barely scraping by. Those who upset the balance must be punished accordingly. I am a demon, so I should die by the hands of a god…but I will not allow myself to die by someone who does not respect my master. That is…embarrassing. So take this loss as an act of kindness from me. The humiliation of being defeated by someone such as myself is more than adequate punishment.”
Turning her back to him, she stepped onto the boat that was tied to a stone pillar and drifted back to the human’s side of the arena. Poseidon also retreated, refusing Ares’ offers to escort him to the medical wing and swiftly returning to his palace beneath the ocean floor. He ignored Proteus’ concerns, isolating himself in his quarters as he…unleashed his anger onto the furniture. They could be easily replaced…but his defeat cannot be remedied just like the splintered wood, the tattered drapes, or anything he had thrown around the room.
He has lost against an imperfect creature. Him, the one who is the most feared and blessed god in the pantheons. How could this have happened?! How?!
Though is the Moon Hashira truly an ant if she had beaten him? No. But there is no use thinking about the wretched embodiment of impurity anymore. He…has lost the match, and in the end it is just one loss for the gods. Humanity will be destroyed, and the divine waters will be restored to their glory once the vermin have been eradicated.
Shortly after he had regained his composure, Poseidon returned to the Grecian’s private balcony to watch the other matches. As he is a god, his wounds healed within a matter of hours…so why could he have still felt the sword in his belly, twisting his insides? Why?
This might be the starting point in his descent to madness. He would remain a silent statue even in the aftermath of his adopted nephew’s death by Jack The Ripper’s hands, and Shiva’s obvious win against Raiden Taeemon while his brethren watched the events unfold in awe and anger.
But no matter how hard he tried to dissuade thoughts about the Valkyrie’s servant, his mind always drifted back to the Moon Hashira. He silently reflected on their fight; he remembered the humiliation when she spared his life, her deadly grace as she released one form of the Moon Breathing Style, her perfection.
[First Name] [Last Name], the Moon Hashira and a demon summoned from the depths of Helheim to save humanity….she was perfection. And Poseidon wanted her.
Knowing that the moon always gravitated towards the ocean would only feed into his delusions that it must be a sign from the Fates that this is his other half. The companion who will be by his side for all enternity. So why does she still dare to stand by Brunhilde and whisper in the demigod’s ear? Why does she converse with the samurai Kojiro, when he had no business being near her, let alone sharing a plate of Japanese snacks and tea?
How dare she smile at the man who had killed Heracles and the traitorous Buddha? She is perfect, there is no need to waste her time teaching her breathing techniques to a brat that went toe-to-toe with Loki in the greenhouse!
When the tyrant of the oceans witnessed [First Name] showing more emotions around the other combatants, he knows must act swiftly or else she will be snatched away by someone else who is lesser than a god of perfection such as himself, or worse be cast aside by her malicious master for the sake of humanity’s survival.
He will make the necessary arrangements with Proteus to prepare his kingdom for the arrival of a new queen.
Bonus Content:
The Moon Hashira is fully aware of Poseidon’s psychotic tendencies and will not make it easy for him to whisk her away like Zeus’ previous mistresses. Nor is she blindly loyal to being oblivious to Brunhilde’s scheming.
She did not live for half of a millennia as an Upper Moon by being an idiot.
I had an idea about kokushibo!reader, how about this one had a weird but cute way of showing affection.......like singing sad songs or with a slight regret behind......
An example of music
Cry,cry my night
That the lullaby come alone
Your eyes doesn't see the exit
Hide yourserf and nap,girl
Sleep on this old wood
The moon shines your way
Meanwhile the sun asleep
Awwww, feel like they’d sing it to mayday. Like Peter B trusted them to babysit mayday just to come home and hear that, The lullaby feels comforting but he can’t help but..feel sad….
