"The King's orders are absolute. Fail to obey, and you will be punished."
30 years ago in the remote Yonaki Village, a black envelope is delivered to a single villager. The command inside threatens to draw the entire population into a terrible tragedy!
Take a deep breath, steady your heart, and prepare for a shocking, terrifying survival horror adventure! The latest chapter in the wildly popular "King's Game: Origin" saga has begun. It all starts here!

Georg and Riselotte are not your typical brother and sister, the former’s a priest and the latter’s “alive” by way of…darker methods. As a result, Rise is stuck in a child-like body. Georg immerses himself in research to free Rise from these chains.

Web graphic novel about a larger than life love story. Every week a new page will be unveiled.

So there's this guy, right? His name's, like, Masato or something. He's got bags the size of suitcases under his eyes. He wakes up one day to find that cloud/sheep things have gone and kidnapped everybody. He also meets this boy/girl/sheep named Dori that's all sunshine and rainbows and stuff. They go around looking for people that haven't been taken by the sheep, with Masato beating sheep along the way with the power of beauty-sleep or something because of a promise he made to his dying mother. How's that for weird?

11 soldiers who are on demilitarized zone search mission. Shut down General Outpost....They should have never gone there

A teacher named Kadomae Kazuma has the principal's daughter Noeda Kanade for his class in a new school semester. At first glance, she appears to be a quiet girl, but she's awakening her aberrant love towards Kazuma? This is a psycho love story that accelerates thoughts and actions.

Yasuto Akashi skipped school the day the games began, after having a fight with his best friend. While his classmates competed in the games at school, Akashi and other students who skipped school must compete in a separate set of games in order to survive.

This series takes place at the same time as part one, but is also continuation of Kami-sama no Iutoori.

From MangaHelpers:

28 July 2061 was an unlucky day for Raiji, in which he was falsely accused of being a groper on public transport. That evening, he joined his friends, Yuma and Osamu, to watch Halley's Comet. The comet appeared to arrive a few hours ahead of schedule, but it didn't just pass by in the night sky. Instead, there was a blinding flash, and all the people Raiji and his friends had been watching with vanished. Not only that, but the area around them was suddenly filled with nightmarish giant mushrooms and twisted human faces. In this new, violent world, the three of them will encounter dangers human and inhuman! [tethysdust]

There is a serial killer in my house!

A group of high-school students had an accident on their way to a trip and died but they find themselves in a classroom with a black sphere.

By day, Ha-Rin is a sculptor and teacher. By night, she turns into the serial killer Sow who, along with her protege Soon-Hee, uses a chat app to ensnare men with sex. After the deed is done, the men are kidnapped and tortured to death, punishment for being adulterers or for using women as if they're objects. But Detective Kim and his team are on these murderers' trails - will the duo's reign of terror be stopped?

Who do you think lives next door? A college student?
A secretary? A foodie? A quiet sort?
Or a killer?

Humanity's peaceful days all at once transform into an unspeakably odious hell.
The sudden invasion of wasp-like insects, along with gargantuan "dolls" wielding their enormous alien weapons, annihilating everyone in their path.
In the middle of the chaos, high school first-year, Iruma Ikaruga, fights to save his best friend and his beloved senpai from the dolls' assault with an unyielding spirit.
However, all that awaits him is despair.
Just what are the enormous puppets known as "Dolly"after?
What fate awaits Iruma?
The curtain has risen on humanity's "puppet show" of unimaginable despair, and the battle for survival has begun.

This manhua is a collection of short stories by this author. It is almost similar to the German Brothers Grimm's stories. However, these hold no morals but are more of a twisted outlook on life.

Plants have taken over the planet.
In 2017, the vegetation in Tokyo rose up and toppled human society in moments.
The few survivors are forced to live in the relative safety of a subway network, but supplies are running low.
Join an average high school student named Akira as he challenges the plants in a struggle for survival!

This world had rules. Rules that weren't meant to be broken. If only we had known those rules, everything could have been avoided...

From Hokutonogun.com and HappyScans:

A former professor of archaeology, Hieda Reijiro was expelled from the Japanese Archaeological Association for claiming that youkai exist. Ancient horrors come to life before our eyes as the youkai hunter wanders the land to find proof for his theory.

The included one-shot, "The Living City", won the seventh Tezuka Award in 1974.

A little girl that murders her abusive family, a doctor trapped in a plane with a violent infectious disease… These stories and more await you in the darkness of this collection of horror by Nori Ochazuke.

From asdf scans:
In near future, mankind has been defeated by the viral parasites named "Gastrea." They have been exiled into a small territory and live in despair, side by side with terror. In this world trapped in darkness Rentaro, a boy living near Tokyo and a member of the "Civil Security"—an organization specializing in fighting against the Gastrea—is used to accomplishing dangerous tasks. His partner is Enju, a precocious young girl. They fight using their peculiar powers until one day, they receive a special assignment from the government. This top secret mission is to prevent the destruction of Tokyo. Set in a near future, this thrilling heroic-action story starts now.