The seven teenagers who committed crimes had their body parts related to the crime they committed taken away and was sent to a school with a locked room. To return to their normal lives, they have to continuously take the examination and graduate as the first in class within one week, or else...

One night, senior high-school second-year Nishina Airi is abducted. When she wakes, she is trapped in an uncanny, isolated space with other students from her high school and forced to take part in the “Werewolf Game”. Thus, a death game filled with fear and terror that would pit “Werewolves” and “Villagers” against each other, force them to murder – a game with rules so absolute, defiance is punished by gruesome death – begins.

From MangaHelpers:
Ichijo Kazuya thought that he was murdered, but when he came to, he was back in his high school days. He lived his entire life as a playboy and had had countless sexual encounters with women until that fateful day that he was killed. He realizes that his murderer was his old high school friend Tanaka Masaki who was jealous of Kazuya’s relationships and his built up anger eventually exploded.
Taken back 15 years into his past, it seems that he has been given a second chance at life and given a chance to make different choices. He decides that the way to prevent his eventual demise is to make sure Masaki is more successful with girls and loses his virginity before Kazuya. But fate seems to be steering Kazuya towards the path of his previous life and keeps introducing the same girls he had sexual encounters with.

From MangaHelpers:
One day, Matsui Sakura receives an invitation to a "Revenge Game," and decides to attend. At the location indicated, she ends up locked in a dorm-like building with four of her classmates. It appears that the Revenge Game is being run by a wealthy classmate, Saionji, who was bullied so badly by some of the students that it ruined his life. Now he is taking his revenge, in a brutal game that allows him to have one of his former tormentors killed each morning.
However, Sakura--a lonely, quiet, orphan girl--does not understand why she is there, unless it was due to her inaction in stopping the bullying of others. She's also the only one who received an invitation, while the others were abducted or tricked into attending. What is the final purpose of this game?

The series follows the adventures of Sabu, a young Edo bakufu investigator traveling with the blind master swordsman Ichi. In their travels, they assist the common people in solving mysteries and righting wrongs (usually committed by bandits or corrupt officials). Sabu is engaged to Midori, the daughter of his boss, who works as a police officer for the Tokugawa shogunate.

This series won the 1968 Shogakukan Manga Award.

From Tokyopop:
When you come from a family of exorcists and mediums, you're expected to have certain powers. But despite having a psychic lineage, Kouhei Midou can't predict the future, nor can he see dead people. He's powerless in every sense of the word. However, he does think fast on his feet--and with a little help from his psychic cousin Seiji, he's an amazing crime solver.
The mystery he wants to solve more than anything is his mother's tragic disappearance. But it isn't easy... especially in this world, where nothing is as it seems. Cats talk, blood-sucking vampires roam the earth, and monsters eat guys like Kouhei for breakfast. Can Kouhei survive this chaos long enough to find the mother that he's lost?!

In Fall 1986, Battler Ushiromiya and eleven of his family members are reunited on Rokkenjima for the purpose of discussing how the head of the family's fortune will be divided upon his impending death. When a typhoon hits the island, everyone is trapped and murdered supposedly by the Golden Witch in her efforts to revive herself. When Battler refuses to acknowledge the existence of magic and witches, Beatrice the Golden Witch, appears before him and challenges him to save his family by proving that neither she nor magic exists. To save his loved ones, Battler is forced to observe the events of Rokkenjima again and explain how all the murders occurred without magic or otherwise submit to Beatrice and acknowledge her existence as a witch.

Aida Shizuka is three days from being executed for cruelly murdering his family when a shinigami comes to visit him. It's his little sister Hibiki, who has come to make sure his soul goes to hell! Hibiki has another job on this trip as well, granting the final wish of a girl with heart disease, and she drags her condemned brother along with her. Soon, it becomes apparent that people are not as simple as they may seem, and even Shizuka's guilt is uncertain. Hibiki and Shizuka promise to search together for the truth about their family's death, and they won't let life, death, or trouble in the afterlife get in their way.

Based on the PlayStation 2 game of the same name. A teenager who was orphaned as a young boy returns to the city of his childhood. Shortly after transferring to Gekkoukan High School, he is attacked by Shadows — creatures that feed on the minds of their victims. He soon discovers that he shares a special ability with other students at his new school. From them, he learns of the “Dark Hour,” a hidden time that exists between one day and the next, swarming with Shadows. He joins the Special Extracurricular Execute Sector (SEES), and with his new friends, confronts the threat of the Shadows.

After being kidnapped by the cult Gorgom, Kotaro Minami were submitted to a mutant surgery with the purpose of becoming the candidates for the next Gorgom Devil King. Kotaro escaped and turned against Gorgom as Kamen Rider Black.

A collection of stories:

1-2. Kaine - Shinogu awakens from a coma in a hospital only to find out that his black hair has turned red and long. he looked exactly as his famous rock group vocalist twin brother - Kaine. Kaine was part of a group called Endorphines. Apparently someone tried to kill the two brothers off. However in a car accident Kaine died on the spot while Shinogu was in comatose state. in order to let Endorphines continue, their manager forced Shinogu to take over his brother's place, hoping no one will know the difference. Or will they? Kaine's best friend Die already started to suspect the fake-Kaine. meanwhile, one by one the fans of Endorphins began to commit suicide after listening to their latest CD. Die and 'Kaine' decide to investigate and are determined to find the truth.

3. Magical Mystery Tour - When a normal Japanese high school girl wins an all-expenses-paid trip to LA, it really does seem too good to be true...

4. Tokei Jikake no Orange Bakudan (The Orange Time Bomb) - Takumi and Gai are members of the popular band, Orange. When rumors of Gai going solo start to spread, tension rises. And who’s this strange girl that shows up claiming she wants to marry Takumi?

5. Tokyo Top - A continuation of the 4th chapter: the story of how Gai met his girlfriend, Satsuki.

From Seven Seas:

Alice in the Country of Joker: Circus and Liar’s Game continues the adventures of Alice as she goes deeper down the rabbit hole to the country of Joker.

Alice Liddell has now entered a new realm--the country of Joker--where she is reunited with old friends. Yet new challenges abound, as Alice must unravel the mystery of the Circus and the Prison Realm, and deal with the enigmatic Jokers.

This is the first Complete Works set for Ito's works released in the late 90s.

The first two volumes contain thematically linked but self-contained stories concerning Tomie - a beautiful young woman with the power to seduce and dominate any male, from small boys to elderly men. Later, the series leaves these characters behind and focuses on stand-alone gothic horror pieces.

From myobi:

China, early Song Dynasty.

The setting is an era of absolute corruption, when bribery, torture, and threats were the normal way of doing business in the government. Then comes forth a young, new Official - Houjou - who challenges the corruption. Gifted by the Emperor with three beheading devices, he is charged with bringing justice back to the courts.

Based on the historical figure of Justice Bao (Chinese reading of the name), who was said to be an incorruptible official, this is a light-hearted romp through ancient China as he and his assistants work against the corruption that has become the norm in the Imperial Courts.

For more on the historical person and legends surrounding him, see:
http://en.wikipedia.org/wiki/Bao_Gong

From MangaHelpers:
The world is in a war against an alien race called "Mimics," who have taken over most of the world with a mission to eliminate the human race. Keiji Kiriya is a new recruit in the United Defense Force, which is battling against these "Mimics." On his first day of deployment, Keiji and his unit encounter "Mimics" and are all killed... Or was it all a dream? For some inexplicable reason, after every time he dies, he is resurrected and returned back to the day before the battle. Why does this happen to Keiji and how can he escape from this never ending cycle?

Note: Nominated for the Eisner award for the "Best U.S. Edition of International Material - Asia" in 2015.

Tsukasa is a magazine writer who has a sometimes boyfriend Atsushi, a gay porn star. They get along just fine, until Yui shows up, a yakuza from Tsukasa's past! Mix in a haunted house, ghost mystery, yakuza action, and plenty of adorable kitties and you have the latest new story from Miyamoto Kano!

From Half-Baked Scanlations:

Ririko, a stylish Charisma Gal from Shibuya, finds herself playing amateur detective after an unexpected turn of events. She is keen to solve cases to prove herself worthy of elite police detective Nii, a man she adores and regards as her fiancé, but her enthusiasm leads her into a whole lot of trouble.

From Viz:
The business of Death is never done. Asato Tsuzuki works as a Shinigami, or "Guardian of Death," in the Ministry of Hades. It's his duty to make sure that the souls of the dead reach the afterlife, but contrary ghosts and humanity's evils keep getting in the way of a job well done. With all these problem assignments, will he ever get a bonus... or will he be stuck paying back damages for all eternity?

Kyoya Ida is a hard-nosed detective from the Shinjuku Police precinct. He is known in the force as an unreasonable type who would use lethal force to solve cases, making him unpopular with the enlisted and high-ranking officers in the National Police Agency.

Despite this fact, there are some in the force that admire Ida for his bravery and cleverness in using lethal force to solve criminal cases whenever legal means are met in a dead end.

Imagine living in a town where supernatural beings stalk the night for their next prey. Toukei Ibun takes place 29 years after Tokyo was established as the capital of modern Japan. Manzou is the owner of an inn in the town of Asakusa. His friend Hirakawa is a journalist who is investigating the bizarre crimes that keep occurring all over the city in the dead of night.