Welcome To Demon School! Nagisa-kun

Police Station

-In the 666th floor of The Tower Of Babel, Before Sullivan got arrested-
Narator's pov

Here we see 3 demons in the 666th floor of the tower of babel, emitting their powerful auras as if they were about to fight each other

Those 3 demons are the 3 heroes of the nether realm. Lady Levi, Lord Beliard and Lord Sullivan. Who were actually holding their own meeting

As the room that was once filled with nothing but silence was broken by Lord Beliard

"Today's the day... We finally come to a conclusion." he said

"Of course... Let's finish this... Once... And for all." Lady Levi said

As the two demons didn't move a single muscle after they declared what they wanted to say, quickly slammed their hand on the table showing things about their grandkids

The two demonic heroes started arguing whose grandkid was the best going back and forth, showing no signs of backing down, getting themselves into a stalemate

As the two were finished with their rants they asked Sullivan to judge again only for him to slowly start laughing getting both of their attention

As they asked him what was wrong only for him to pull out a picture of nagisa and said "WHAT'S WRONG IS THAT YOU BOTH ARE WRONG AND MY GRANDKID IS THE BEST!!!" shocking the two as they started asking questions

"WHAT?!" the both of them exclaimed

"I know, right! I just found out about it recently." Sullivan said with a smile looking at the photo

He then starts taking out photo albums of Nagisa from the past and as of now

The three looked at the pictures of Nagisa and they instantly said "Cute."

"I know, right! Look, Look, Look, he even got my eyes and smile." Sullivan said with a smile pointing at a smiling baby nagisa

"I can see some similarities but this feels too unreal." Beliard said steoking his beard

"Is it really yours?" Levi asked

Sullivan just smiled and then pulled out a letter, and 2 pictures "A letter from my son as well as a picture of him with his family and our family picture." (The same one Sullivan showed to Nagisa at his apartment)

"It really is yours..." the both of them said at the same time then started thinking of ways to break the now 3 way tie, leading to a talk about who will be the next demon king, only for it to end with no one becoming demon king again

As they ended the meeting, Sullivan started to skip out the door chanting "I'm going to see my grandson~" over and over again only for him to stop at his tracks as the doors opened with red haired glasses wearing demon stated "Pardon me. Lord Sullivan, my daughter has been under your care in school. But... Your under suspicions of illegal visits to the human world. May I have you accompany me."
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-Present time at The Demon Police Station-
Nagisa's pov

As we arrived at our destination, Opera first got out then helped me get down safely

As I looked around and saw a large threatening building casting a shadow over us

"Let's get inside, Nagisa-sama." I heard Opera said as he was walking to the building

To say it was scary was an understatement. It was HORRIFYING! The whole place was filled with demons looking like delinquents. I'm just happy that Karasuma-sensei taught us how to keep a straight face

We were instantly led into a room with a one way mirror and filled with demons again looking like delinquents as well as a red haired demon was sitting on a chair and on the other side of the mirror was Grandpa tapping his finger asking if I was here yet

"You must be Nagisa?" I heard someone call my name

"Yes?" I answered looking around to see who called my name

I saw the red haired demon stood up from his seat and was starting to walk over to me

Opera put me behind his back and was ready to attack while I set my ring to it's third setting and was getting ready to suck the demon dry of his magic

Then at a blink of a moment the wall with the one way mirror was broken and Grandpa was right in front of the red haired demon's face, his hand ready to slice his throat open

"WhaT ArE yOU doInG sCaRRiNg mY GraNDsOn?!" Granpa said in a very threatening voice as the room temperature suddenly dropped

The red haired demon quickly lifted his arms up in surrender "I just wanted to talk to him, Lord Sullivan." He said as sweat was dripping from his head

"Grandpa, let the man go... Please?" I said praying he would do as I said
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Narrator's pov

Sullivan quickly did what Nagisa said and went straight for a hug which Nagisa happelly complied

Then Nagisa asked what was his Grandfather doing in the station which the red haired demon which happens to be the head of the police said that they had suspicions that Nagjsa's grandfather was illegally visiting the human world

Which shocked Nagisa then looked at his Grandpa in confusion which Sullivan just chuckled while scratching the back of his head

Nagisa quickly asked for them to talk privatly with the chief of the police in which the chief said that his office is a good place

They went into his office and Nagisa said to hos Grandpa to tell the demon what happened which Sullivan quickly denies specifically saying it was for Nagisa's best interest but was countered by "If it's for my best interest then Grandpa would be with me there to protect me when I still can't." getting a sigh from Sullivan and said "Okay." as he started to explain about how his son had a kid with a human at the human world and about Nagisa being that kid and that he was the last living relative of Nagisa since his mother died getting complete custody of nagisa

The red haired demon chief sighed and started to explain that since nagisa was half demon they could have helped him find his grandson and legally visit the human world to help search as well which Sullivan said that he got too excited

The demon chief sighed and said that since Nagisa is half demon then he legally is a demon  and there's no crime with that but Sullivan still illegally visited the human world

Then Nagisa started bargaining with the chief getting a minimal punishment of doing the necessary documents for the visits as well as for Nagisa's legal documents (His birth certificate, adoption papers and etc.)

And to top it all off, the chief was to remain silent about Nagisa's heritage which he quickly agreed to

After their talk, it was late at night and Nagisa was asleep. Getting permission from the chief to start doing the paper work tomorrow, the two demons started flying off back to their house with a sleeping Nagisa safely held on his Grandpa's arms

As they reached home, they quickly changed his clothes with magic and tucked the sleeping half demon on his bed. As they were about to close the door, Sullivan said "Goodnight, my precious grandchild." then closes the door letting the boy sleep the night away