Japanese title: 最凶の魔王に鍛えられた勇者、異世界帰還者たちの学園で無双する
Publisher’s official English title: A Hero, Trained by the Most Evil Demon King, Fights in a School for Those Who Have Returned from Another World
Publisher page: https://firecross.jp/hjbunko/series/438
BookWalker page: https://bookwalker.jp/series/321839

Volume 1 cover:
Volume 1 cover

Update: Volume 4 was released, and the manga adaptation started serializing since May 2023.

> LN VOLUME 4 Cover Illustration

Release Date: May 18, 2023

Quick info about the manga adaptation:

Story & Art: Mimori Tsukahara (“Re:ZERO -Starting Life in Another World- The Frozen Bond” Manga)
Start Date: May 18, 2023
Status: Ongoing (5 chapters)
Magazine: MangaUp (Square Enix)

Synopsis: Amidst a turbulent era, the kingdom of Amelia, led by Queen Amelia, holds a monopoly on the extraordinary power of 'magic' and relentlessly invades other countries. Meanwhile, the prosperous small nation of Campus Fellow thrives on farming and blacksmithing but now teeters on the edge of war.

In a desperate bid to ensure the survival of their nation, Lord Bud Grace devises an unconventional plan. He resolves to assemble a group of wicked “witches,” known for their terrifying tales and catastrophic powers, to join his cause. Among them is a boy raised as an assassin, known only as the “Black Hound,” equipped with a deadly arsenal of killing techniques. Despite the perilous nature of the strategy, he willingly dedicates himself to protecting his country and his lord.

1st chapter is available for free (JP):
Manga UP | Author's tweets

@Lily-Garden This is the kind of title I want as part of my physical collection...!

@tahu Might I suggest you make a topic for each of those titles (assuming there isn't one already for them), it's difficult for people to show support for a specific title when you've listed 4 of them.

Also while there's no standard template, it's helpful for people if you could list the publisher, the number of current volumes released in Japan (maybe the year publication started), if it's ongoing, completed, stalled, cancelled, a summary of the series and maybe a little blurb about what specifically drew you to the series.

Otherworld Nation Founding Chronicles has a topic, though based on the replies it seems like the LN stalled at 4 volumes and was cancelled.
https://forums.j-novel.club/topic/1180/異世界建国記-isekai-kenkokuki

異世界に転移したら山の中だった。反動で強さよりも快適さを選びました。
Isekai ni Ten'i Shitara Yama no Naka Datta. Handou de Tsuyosa Yori mo Kaitekisa wo Erabimashita.

@wellwisher Chapter 11 is where he's fighting a guild in the dungeons. I def felt the manga may have watered things down.

Read the WN a bit, well, as much as has been translated. Starts off well enough though hard to tell how it turns out. Unfortunately, chances of getting licensed are very low.