Against Heaven - Chapter 5

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

“I will have my vengeance, in this life, or the next!”Albedo died alone and depressed and was reborn in a Novel he had been reading. However, instead of becoming the Protagonist or Antagonist, he becomes Albedo Neverwinter, an Extra he couldn't even recall from the Novel.However, the cruelty of life didn't change even after rebirth, and his new family was ripped away from him, leaving him with nothing but scars as reminders of the gruesome fate his family faced.Promising to get his revenge, watch as Albedo, alongside his System, his tactical mind and scarce but valuable future knowledge, rises up the ranks and ascends the pyramid of power.[ OP MC, System, Harem, Romance ][ Yeah there will be Smut, but it won't dominate the Novel ]

Kōdo Ikusei Senior High School, a leading prestigious school with state-of-the-art facilities where nearly 100% of students go on to university or find employment. The students there have the freedom to wear any hairstyle and bring any personal effects they desire. Kōdo Ikusei is a paradise-like school, but the truth is that only the most superior of students receive favorable treatment.

The protagonist Kiyotaka Ayanokōji is a student of D-class, which is where the school dumps its “inferior” students in order to ridicule them. For a certain reason, Kiyotaka was careless on his entrance examination, and was put in D-class. After meeting Suzune Horikita and Kikyō Kushida, two other students in his class, Kiyotaka’s situation begins to change.

One day, I woke up only find out that I’d become a Demon Lord, an individual responsible for protecting a dungeon. The world I’d been spirited away to was one filled with violence. Gigantic monsters wandered through it and competed with each other each and every day for the right to survive. I had no choice but to strengthen my dungeon’s defenses in hopes of living another day—or at least that was what I’d thought. For some odd reason, I instead ended up spending my days in relaxation and bliss.