A small group of adults have been invited to a reunion at their old high school to remember the loss of their classmate Kiriko, after receiving a letter "From K."

Not knowing who "K" is, Ryosuke, a young man with short black hair that used to know Kiriko, has to uncover the truth of Kiriko's mysterious death. As he slowly regains his memories and his fellow classmates start suddenly dying around him in the most horrific manner, he realises that it's far too late to say sorry.

From Shinnen:

Naraka High School is a seemingly normal school. However, unknown to the public is the cruel truth of what really goes on in the school's halls. Rather than studying, students are forced to struggle for their very survival. And the strong bonds of friendship may be the only difference between life and death.

A manga adaption of the Betterman anime.

Dolls Fall revolves around the lives of students at Jiaiin girls dormitory, an orphanage for middle school children without families. They are greeted with open arms by the matrons and other students, taught to accept their fellow orphans as sisters and the matrons as their mothers.
Jiaiin is a safe haven for students, provided that they follow two simple rules: at night, lock your door and don’t leave the room, and never enter a matron’s room.

A group of high school girls conduct a test of courage for kicks, but something dangerous begins to threaten their everyday life.

A traditional suspense horror begins!

Humanity wakes up to find that they've all shrunk. Can they survive amidst the hazards that Nature entails?

This is the story of young Alice and her protective dog Poco in this new world.

A one-shot about a strange curse visited on a family after an archaeological dig.

One-shot in celebration of 30 years of Itou Junji's career.

From MangaHelpers:
The high school columnist looking for the next big story gets more than she bargained for when she digs into the wife of a man she meets. The female anime characters that the class nerd draws become real and over protective of their creator. The monster behind the old child’s story haunts the people that break the rules of the contract. These are some of the episodes in this collection of short horror stories.

This manga is based on the Majo no Ie - Ellen no Nikki (The Witch's House - The Diary of Ellen) novel that author and game creator Fummy released as a prequel to the creator's own Majo no Ie horror puzzle game. The original game casts players in the role of Viola, a girl who wakes up in the middle of a forest, where a path of roses leads her to the house of a witch named Ellen. She enters the house, and must find a way out again. The prequel novel centres on the story of how Ellen became a witch.

(Source: Anime News Network)

Sugawara has terrifying dreams of bloody murder. What could these dreams be about?

A new adventure begins for Professor Hieda Reijiro, who is also known as the yokai hunter. On Kami Island, there are strange legends of the Taira clan and the Sea Dragon. After a man goes missing for three days, Hieda goes to visit the island and uncover the truth of these legends during the superstitious Sea Dragon’s festival. Between strange fish washing ashore and intense rituals, this investigation is sure to be a wild ride!

From Dragon Voice Project:

The word "Lore" means rumors, urban legends. That is, stories spread by word of mouth. The only ones who can reach "The Forest of Lore," a site that collects these stories, are the invited and all who have anything to do with this mys-terious site are visited by misfortune. Eiko, after getting lost in the Forest of Lore, is now looking to see if there are any rumors about her school... Are they real, or are they fake?

A collection of short stories.

"Help me paint a portrait of my true face!" demanded a man named Sein as he appeared in front of the painter, Lou on a street corner. Living together as a patron and an artist, Lou discovers that Sein is actually a vampire. After getting to know him, Lou begins to hope that Sein would drink only his blood, and no other's. However, Adam, the mysterious man who seems to be very close to Sein, might have something to say about that.

English publication via Renta!

In grade school Juuzou was tortured by his classmates and develops an alter ego. Years later, Juuzou has to work with one of his bullies named Akai, who move into the apartment above his. As time progress Juuzou's revenge minded alter ego takes over and becomes a psychopathic killer. Made into Live action movie in 2005.

Nakanishi searches for the truth about a classmate's murder so he can settle a grudge for her.

Alma is born a witch after her father makes a deal with the demon Mephisto. She seems to be able to travel through time and goes back to the middle ages in Europe, the Mayan / Aztecian time as well as the Roman ancient time and Nazi Germany.