Reborn in black clover with Demon Slaying magic

Walking back into the restaurant after leaving the church, the sight of a small red haired boy sitting around one of the tables eating porridge entered Grim's sight.

"Yo Marco." Grim called out.

Marco was one of Rebecca's younger siblings, he was quite a shy boy and no where near as annoying as his older sister.

"Hey Grim." He smiled a waved.

"Where's your sister?"

"She said she had to go get some supplies."

"Oh? I guess that means its just you and me little man."

"Mmm." He nodded and focused back on his porridge while I went behind the bar and poured himself a drink.

---

-1 week later-

"Are you ready?" A white haired old man looked over Grim with appreciation in his eyes.

"Why ask? He's spent so much time relaxing that he should have enough energy to last a life time." Rebecca spoke up much to Grim's annoyance.

"Sis!" Marco whined.

"What? Its not like what I said wasn't true."

Holding back his urge to show that he was an advocate for gender equality, Grim merely smiled and said his goodbyes. After spending the past 3 years training with Theresa, he was already prepared for the entrance ceremony. And while he may not have much memories of what happened in the manga, he knew for sure that this moment would define his role in life, He just hoped that God didn't screw him and give him something like a one leaf clover... Knowing that fucker, Grim could actually see this happening.

---

'Finally here.'

Standing inside a huge library like setting, Grim was surrounded by a large amount of young people who were in the same age group as him. A lot of them were like him, curious with a hint of anticipation on their faces. Others looked scared and shook with worry. And then there were the ones that took a knee and started praying.

'If only they knew that God wouldn't answer their prayers. I wonder how they'd react?'

Now that he thought about it, he wondered why they had to get their grimoires when they turned 15. Was it some rule of this world? But if so, what was so special about being 15?

While he was thinking about this, he didn't notice that somebody had appeared in front of the grimoire-less teenagers. The guy then proceeded to spout some bullshit about how special grimoires were and how they should strive to better this kingdom.

"Now then, let the Grimoire acceptance ceremony begin!" Once the man stopped speaking, the books on the shelves started to shake and radiate different colors as they took to the air before finding their way to their respective owners.

Feeling his attention being drawn elsewhere, Grim turned around and saw a 3 leafed grey grimoire surrounded by soft white light floating in front of him at chest level.

'Is-is this my grimoire?'

As if reading his thoughts, the grey grimoire pushed itself forward and into his hands. Feeling the book hum in his hands, the grimoire suddenly opened up and revealed two different pages showcasing his new found spells.

---

"So how'd it go?!" The boss appeared in front of him as soon he stepped through the restaurant door.

Hearing the noise, Marco and Rebecca also came over.

Instead of answering the manager, Grim merely smiled and summoned his grimoire.

"Ahahahaha, you succeeded!!" The boss cheered.

"Congratulations Grim." Marco added.

And he could have sworn that he saw Rebecca smile for a minute there.

"So? What spells do you have?"

"Watch this." Focusing his attention on his grimoire, he felt the mana in his body gather around his hands as two serrated blades materialized in his hands. Watching with amazement, the three onlookers felt their eyes widen as the looked closer at the jagged swords in his hands.

"S-Swords! Why the hell do you have swords! I thought your magic was body enhancement!" Rebecca suddenly exploded with questions.

"Just because I can enhance my physical ability, it doesn't mean its my magic." Grim said with a smug look on his face.

"Y-You!"

"So cool!" Marco's eyes basically shone as he looked at the swords that were radiating grey light.

Grinning at their reactions, Grim let the swords dissipate into nothingness and de-summoned his grimoire.

"EH!!"

"Sorry, but I've gotta go train." Leaving them with a look of surprise on their faces, he left them to their own devices and closed the door behind him.

---

"Okay you old bitch! Lets do this!!"

"Grim?" Seeing the black haired boy kick open the church's front door, Marie and the other kids looked at him with surprise.

"Oh? Hey guys, where's sister Theresa? She got a date with destiny." He grinned wildly.

"She's planting some flowers."

"Thanks!" And just as he appeared, he disappeared just as fast.

---

"Someone's happy." Crouched down with her back turned to him, Theresa smiled as she covered a seed with fresh soil.

"Cut the crap! You know why I'm here."

"Of course I do, you're here for another beating."

"Not today."

"We'll see."

---

Raising her hand slightly, Theresa released a stream of flames towards the distant Grim.

Unable to hold his smile back, Grim's body was covered by a soft gray glow as he charged towards the flames while his swords materialized in his hands.

Using his now enhanced body to jump over the stream of fire, he leapt high into the air and came crashing down towards the old nun.

Seeing this, Theresa smirked thinking that he was too hasty in his reaction. Now that he was in the air, he had no way to dodge.

Lifting her arm up higher, she released another stream of fire at the airborn Grim.

Watching the torrent of flames approaching him, the smile on Grim's face grew wider as he activated a spell.

[Second Fang: Rip and Tear]

Performing a diagonal X slash with both blades, Theresa and the spectating children watched in shock as Grim's blades seemingly tore the torrent of spiral flames apart.

"WOAH!!" The kids exclaimed in shock.

Dumbstruck by what she had just witnessed, Theresa quickly snapped out of her stupor and quickly casted a spell called Shining Flame Cross. Using multiple small explosions that took on the shape of a cross, Theresa erected a flame shield to protect herself seconds before Grim's blade reached her.

'Oh shit.'

"DETONATE!" Theresa looked up at him through the gaps of her shield and yelled.

*BOOM!!*

Flung backwards as a result of the shockwave, Grim's body smashed heavily into the ground as steam escaped from his smoking body. Luckily for him, Breath of the beast allowed him to take the brunt of that attack without suffering any real damage.

"Hahahahahahaha." He laughed loudly as he lay flat on his back. "I finally got close to you!"