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.

Struggling manga author Satoru Fujinuma is beset by his fear to express himself. However, he has a supernatural talent of "noticing things" that forces him to help people.

Boku dake ga Inai Machi Gaiden

From JanimeS: Princess is a very straight forward and sad series. This series is full of romance and politics. The background is an unknown medieval era where there are three countries. Among the three countries, there is an island country called "Ramira". The empire, Ramira, is where most of stories will unfold. There are generations of princesses, and the first 27 volumes set the story for the eventual regaining of Ramira by the greatest Empress of Ramira, Preia, who was beloved by the people and had many loyal men under her.

A story about a girl being kept in isolation in a world that appears to have experienced an earthquake and nuclear disaster.

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 Easy Going Scans:

A tragic young girl whose mother died giving birth to her.

A wicked stepmother and three brothers with whom she shares no blood ties.

Murderous intent born from avarice and twisted emotions.

Secrets woven with betrayal, terror, deceit, love, death and vengeance.

All buried deep within Ayeshah's Forest, shrouded in darkness...

The impossible happens in 15th century Korea.

A princess who was disguised as her dead twin brother by her mother became king. Once her true gender is found out, the female king is sentenced to death by drinking a lethal dose of poison.

This story details the events of that forgotten king's life.

From Jcafe24: Corpse Party: Blood Covered is about a group of high school friends in Kisaragi Academy. Kisaragi Academy was built on the grounds of Tenjin Elementary School, which was demolished after a string of disappearances and gruesome murders. After a mysterious earthquake, the students find themselves trapped in an alternate reality Tenjin Elementary School, where the murders of others trapped before them have continued unabated...

As working woman and plant fanatic Sayaka Kōno was heading home from a drinking party, she found a handsome man sitting in front of her apartment who says, "Please bring me home with you," like a dog. With no place for the unnamed man to go, the two begin living together, and their "delicious" love story begins.

Sihoon is a boy who lost his parents and lives with his older sister. This story begins as he meets Mephisto that came to the world to find Faust and makes a deal with Mephisto to supervise the fights between Mephistopheles and Faust.

From Aerandria:

Mermaid is a beautiful blind girl from a very wealthy family who has constantly been sought after by rich gentlemen who covet both her wealth and beauty. To finally make them stop, she agreed to marry the one who can make her hear something amazing and unheard of before. As each gentleman fail one by one, one particular man of common origins resolves to make her wish come true. See to what lengths love will go for the heart’s wish…

A spiral love story. Kouno Jun is a lively character who lives life with all his might. In kindergarten, he falls in love with Hasebe Rino, the most beautiful girl in his class, and he confesses to her. Hasebe accepts his love, but the moment she gives her answer, she vanishes on the spot. Failing to figure out what's going on, Kouno asks his friends about Hasebe, only to find out that no one remembers a single thing about her. She has just vanished, along with all memories about her, except for those of Kouno.
While Kouno leads a weary and desperate high-school life, Hasebe appears again as a transfer student. However, this Hasebe is not exactly the Hasebe he knows.

1) Passion Kiss (Yokujou Kisu One night) -
Manatsu has a dream of an incredibly fulfilling kiss. "Who was the boy in my dream? That's the first time a kiss has made my chest ache." That's when Manatsu gets a feeling from her classmate, Morishima-kun -- the same feeling she got from the boy in the dream. Without thinking, and despite the fact she already has a boyfriend, she... (!!!)

2) Second Virgins (Sekando Vaajinzu) -
Kawori is prepped and ready to lose her virginity to Shunsuke... until he penetrates her and it hurts like hell. She wants him to stop, but he can't. They get into a fight and stop talking after that. Then, one and a half years later, Kawori gets coerced into attending a singles party -- and Shunsuke is there! ...As the boyfriend of Kawori's friend Nao? How will Kawori and Shunsuke handle their unresolved feelings?

3) Eternal Summer, Fleeting Summer (Eien no Natsu, Isshun no Natsu) -
The first love letter Takeshita Riho wrote was to Sakurai Touma, the class president she had a crush on from second to sixth grade, but the letter never got sent. ...Until now, when Riho's meddlesome friend mails it out. To Riho's surprise, Touma writes back and responds well to her feelings! He's just as Riho remembers him, and the way he writes makes it sound like those elementary school days were the most important of his life. What Riho doesn't realize is the heart-breaking (and tear-jerking) reason why...