I Stayed At Home For A Century, When I Emerged I Was Invincible - Chapter 8 - Cultists, pawns!

Four years ago, Kazuma Kannagi was defeated by his cousin Ayano Kannagi for the right to be the successor of Enraiha, a sword passed down in the Kannagi family. His defeat, along with his lack of talent for En-Jutsu, the fire arts, the Kannagi’s specialty, resulted in his banishment from the family. Now, Kazuma returns as Kazuma Yagami, a skilled master of Fū-Jutsu, the wind arts. At the same time, a number of murders at the Kannagi residence perpetrated by a powerful Fū-Jutsushi cast suspicion on him.

Volume 1-6 makes up the main story. Volume 7-12 are various short stories, also known Kaze no Stigma Ignition.

Note: Only v4 epilogue remains untranslated for the main story.

Florentia was reincarnated as the illegitimate child of the richest family in the empire.

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 want to run away from everything."