Prologue
Black clover world.
In clover kingdom, everyone is being attacked by magic knights. They have a strange glow aura, a symbol on their face, pointy ears. Look like they weren't themselves anymore. They called themselves Elfs.
Meanwhile in the stone castle.
There is a devil. Everyone is fighting it. The wall is covered by some strange purple thing.
There are two boys are fighting the devil. A boy, who is holding the large sword is being covered by strange black energy. His right body is covered by black energy. His name is Asta. He couldn't control the large sword.
Two monsters show up to attack Asta. Suddenly, another boy showed up and killed them. He has his left body covered by green energy and holds the green sword. His name is Yuno.
"Hey, what's with the light? No fair, Yuno!" Asta asked his friend.
"You just need to concentrate on finishing the devil, you moron" Yuno told his rival-friend.
"I know that, you handsome jerk!" Asta said with a confident smile.
The devil's body covered by a lot of mouths and each them said:
"Your sword can't reach me"
"Already…Just like that…"
"It's over"
"Please win this, Asta" The girl with the horns on her head believed in Asta. Her name is Nero.
'Is Asta at his limit?' Yuno thought about Asta's form is at the limit. Asta still can't control his large sword.
"Asta, I'm gonna leave you behind if you can't keep up!" Yuno told him and flew straight to the devil.
"I'll win this!" Asta's sword grew bigger "Anti-magic demon slayer: Black divider".
"Where do you think you're going, Yuno?!" Asta followed Yuno.
"But you cannot pierce my heart with that wind" the devil thought himself "That anti-magic brat is merely letting himself be pulled along with that wind magic. He's hopeless".
"Huh? Where's the anti-magic brat go?" the devil looked around. Asta appeared behind him.
"He's in my blind spot, coming from a different direction!" the devil looked at both side
Two boys rushed to the devil. The devil is about to use his magic but got hit by both sides.
Suddenly, black energy on Asta's right body is gone even his large sword grew back to normal.
'I reached my… limit' Asta thought himself. "Asta!".
They both got held by the devil. Suddenly, the man, who holds katana. His name is Yami Sukehiro, who uses dark magic. He has been charged his ultimate attack.
"Mana Zone…." Yami activated his Mana zone and sensed devil's Ki. His katana is covered by dark magic.
"Dark Cloaked Dimension Slash – Equinox!" Yami launches his attack.
The attack is cutting through the rocks and cutting the devil into half. Everyone was shocked
"This Ki … It's Captain Yami" Asta shocked about this.
The girl with the horns appears and uses magic on Asta "Sealing Recovery Magic … Healing Prison: Faint Omen".
Yuno uses his sword to cut the devil's hands "You go ahead and do that!".
"Asta. You're going to be the Wizard King, right?" Nero asked him.
Asta covers his right body with black energy and grows his sword bigger again.
"Right here, right now … I'll surpass my limit!" Asta cuts the devil's heart
Everyone is relieved that they defeated the devil. But the devil uses his last magic.
"Word Spatial Magic: Dimension Portal" the devil open portal for Asta. Asta tries to run away but the devil uses his magic on Asta and makes him unconscious.
Asta got sucked into the portal. The sword on the leader of Elf's hand got pulled into the portal too.
"Asta!" Yuno tries to save him but It was too late. The portal has been closed.
"Ke Ke Ke" the devil slowly faded away.
"ASTA!" Yuno has lost his rival-friend.
In Splatoon dimension.
Meanwhile at Squid Sister's house.
"Marie!" the girl with black and some black and pink dots on tentacles hair. Her name is Callie.
Another girl with white and some black and green dots on tentacles hair. Her name is Marie.
Marie sighed and said "What is it, Callie?".
"I'm bored, Marie. Can we play something?" Callie asked Marie.
"How about going to the park?" Marie told her.
"Yeah! Let's get going!" Callie said in a cheerful voice.
"Alright. Let me prepare …" Marie got irrupted by something that crashed outside their yard.
"What's going outside?!" Marie said.
They both go outside and see there are three weapons that they have never seen. Next to them is the inkling boy with ash-blonde tentacles hair and some black and white dots on it. He wears a black headband on his head and a black robe with a bull logo. His common outfit consists of a plain white tunic with a V-shaped collar underneath a dark blue jacket whose sleeves extend only up to his elbows. He sports a pair of matching shorts which has a stitch mark on the left side. His pants also extends just below his knees. His shoes are made out of two different cloths, the parts covering his ankles, the soles the same color as his jacket and pants. The parts covering his toes are white, a vertical stitch mark going from the bridge to his toes.
"An inkling boy? And what are those weapons? I have never seen them before" Callie asked about three strange weapons.
"It doesn't matter. He is injured! We need to fix him up! Help me carry him inside!" Marie told her and Callie nodded. They both carry him inside and bandaged him.
Notes: Forgive me for bad grammar.
Asta will not have his grimoire in Splatoon. He will have three swords. They will be different. Some inklings or octolings or other species can't carry his weapons, they only accepted their wielder just like Black clover.
The Demon Slayer's hilt and blade will be covered by some inks. The swing is slower than the Dynamo roller. They swing like Roller, they cannot roll but the damage is very high. Asta's speedrun on this weapon will be slow. Also, this sword can block an enemy's attack
The Demon Dweller's line will have some inks on it like Asta uses Noelle's magic on Dungeon. The swing is medium like Carbon Roller. This weapon can create [Color] Splash by swing it hard like Black Splash in Black clover. Asta's speedrun on this weapon will be as same as Octobrush's speedrun.
The Demon Destroyer's tip will be covered by some inks. The swing is fast like Inkbrush. He will swing two times and the third one is thrust. He thrusts his sword will make an ink road like the charger. Thrust's range is longer than E-Liter but the ink bullet is faster than Charger's ink bullet. His speedrun on this weapon will be as same as Inkbrush's speedrun.
Two of them can create Splashdown by superjump and slam the sword on the ground. The Demon Slayer's Splashdown is bigger than the normal Splashdown. The Demon Dweller's Splashdown is as same size as a normal Splashdown.