Infernal Entity: Evolving With My Demonic System - Chapter 51: Firestarters

Steven awakens to a nightmare. Transported to a brutal medieval kingdom on a faraway world, he wakes up as Kivamus, the exiled third son of a Duke. Now he’s the newly made Baron of a crumbling village called Tiranat, in a bandit-ridden frontier located within untamed forests. Here, survival is a daily battle, resources are scarce, and technology is a distant dream. Yet, he sees potential where the villagers only see struggle. He dreams of using his knowledge to forge a new future for Tiranat, a future fueled by industry. But the path to progress is not going to be easy. Managing a starving village in the coming winter and navigating the cut-throat world of medieval nobility is just the beginning. This is a slow-progression kingdom-builder story, with a lot of focus on worldbuilding and eventually, industrialization and tech-uplifting. The story is going to be very, very long. Settle in for a slow-burn slice of life, where the journey is just as important as the destination. Welcome aboard!

A tree of 10,000 flowers, the world is the door.
The spells change a lot, but the hearts of the people are unchanged.

- Description from Uukanshu translation

The world is terrorized by the powerful Black Witch who has been sealed in the moon. Every ten years, the night of Hexennacht arrives and a chosen witch must battle the Black Witch in hopes of finally defeating her.

As the current decade’s Hexennacht approaches, a mysterious girl named Kagami Kagami arrives and meets Horinouchi Mitsuru, the daughter of the previous Hexennacht representative.

It takes place between Kyoukai Senjou no Horizon and the City Series, two other series by the author.