While Japan in desperate situation, 13 "devil survivors" cut deals with devils to obtain abilities to fight against unknown invaders with only 7 days left until a world catastrophe, you need to make crucial decision to survive...

Kinda creepy. Dante, the main character, is fighting various characters to keep the passage to the demon world sealed, but he doesn't seem to be having much luck... (And the story says 'To be continued' at the end, so there might be more to it.)

In the midst of a terrorist attack that kills all his classmates,Tohru Kuroe knows the chances of seeing yet another woman die makes Tohru pick up an abandoned gun - The beast awakens; taking over. When Tohru comes to his senses, he finds he is now a killer. Finding out he was genetically engineered to be a killer, his codename is D-17, Tohru continues his 'normal' life amidst challengers threatening his life and those around him.

From Horobi no Michi:

Clockworkers- mechanical men, created during the war as a weapon to kill as many as possible. That war may be long over, but rogue Clockworkers are still roaming about, spreading fear and death wherever they go.

Machina's a member of the CWA, an organization dedicated to the destruction of these rogue robots.

Along with Deus, her Clockworker partner, she travels the country in pursuit of these dangerous robots...

Gambling. Mahjong. Death. These are the themes of this fast-paced, undercover-agent-style manga where outrageous life-or-death gambles are made daily occurences and insurmountable odds are overcome. The most hardcore, action-packed mahjong manga you will ever see.

Included in the manga is a oneshot called Nana-chan Scrambles.

A pirate ship that cannot be sunk led by a dying Captain who will not give up. His final wish before he dies is to find the legendary Devil's Eye. And who does he appoint to lead his fearless crew in search of the lost treasure, but Olivia Soldana, a brash 16-year-old girl who can outdo any man.

Kazune joins the band KEEL and becomes their vocalist. But only after a while he is leaving to join the band BLANCA. Why is Kazune leaving suddenly? What will the members of KEEL think of him?

From ShoujoMagic:

Omori Mio is 17 years old. To help out her desperately poor family, she takes on a part-time job. Then, one night, a boy snatches a kiss from her and offers her money, saying, "I'll buy you." Who is the boy who stole Mio's first kiss...!?

An extra of S.P.Y can be found inside.

[From DMP]: Toru is a shy and quiet student who has developed a special crush on his close friend Ryoji, the most popular member of the high school swim team. In front of Ryoji, Toru hides his feelings and acts as if he is just one of Ryoji's good friends, but in a moment out of the blue his world will be turned upside down as Ryoji will confess a secret desire for Toru. Dazzled, Toru can barely hide his excitement for Ryoji and quickly accepts his offer. As time passes, Toru's happiness begins to fade knowing that his affair with Ryoji was just a fling based out of Ryoji's sexual curiosity. Toru, adamant about his feelings for Ryoji, confides in another one of his close friend, Kashiwazaki, about his dilemma. The two set off to devise a plan to test Ryoji's true intentions by faking a romantic relationship. Soon after, a frustrated and jealous Ryoji attempts to pry Toru out of the arms of Kashiwazaki. Is it just as they planned? Yeah! That is of course until Toru realizes Kashiwazaki wasn't really faking! How could he not have seen it coming? Both Toru and Ryoji have hidden their feelings from each other in the past, but now they have discovered that they were not the only ones. Will Toru and Ryoji be reunited or will their true feelings for each other go unfulfilled?

A collection of three stories of love and the supernatural:

I. Desert Storm. It's four years after the Chechnya revolt against Russian rule. Eimi finds a mysterious boy who speaks Japanese, just like her father. Because he can't recall who he is she calls him "Yuuji." And Yuuji's strange powers tell Eimi her first crush is still alive...
*Related to Silent Eye

II. The Garden of Wild Roses. Garden designer Shindo Chika is surrounded by mystery. One by one people she knows are injured or suddenly die. The only clue she has is a boy with a scarred face--who she fears is a shinigami.
*Related to Towa kamo shirenai

III. Sunset Encounter. Ryuugi dreams each year on his birthday of a girl named Fumika who he loved as a boy name Sou, and another boy named Keishi, who kills him. But when the people from his dreams keep appearing and he starts dreaming events that take place while he dreams, then he begins to wonder what exactly is happening.

DeroDero is the story of a juvenile delinquent, Hino Mimio, who happens to also be a psychic. His ability to communicate with the spiritual world as well as his demeanors caused him to constantly interact with supernatural beings -- usually ending up with Mimio beating the crap out of the monster or spirit.

From xkazemg:

Ootome Hime’s father was a jockey who dreamed of winning the Japanese Derby. One year, when Hime went to watch him race in the Derby, he died in a horrible racing accident. The man responsible retired in guilt from being a jockey.

10 years later, Hime is in high school, and she has heard that Arakawa Jin, the son of the man who killed her father, is debuting in the Derby as a jockey. She went to see him race, and was outraged to see him win! Now Hime has decided to quit high school and go to a special school for jockeys, in hopes of being able to beat Jin in a race one day. She has met a new friend and aspiring jockey along the way, a boy called Tadano Ryouhei, but she can’t let him stand in the way of her revenge!

Kenichi is a high school guy who wakes up in a magical land. Together with a fairy and a swordsman, he must recover two magical items to save the magical world as well as his own.

note: The manga has been reprinted in a normal tankoubon size with only Akiyama Tamayo noted as author.

*manga is based on a true story and the true story was done in 2ch*

It's about an Otaku guy who fell in love with this beautiful lady and tries his best to get that girl with a lot of help from 2channelers (people who goes/posts on 2ch).

This story has become very famous in Japan and I believe they now have novels, several series of Manga (both Shoujo and Shounen), movie, drama, play, etc, etc.

This total loser, Tatsuhito, causes the legendary gang leader of the Grand Cross, Shou, to be hospitalized. He must take his place for the duration of time it takes for Shou to recover or else the Grand Cross would fall into chaos.

A collection of short, bittersweet love stories, including several incestuous ones:

1) Until the Ice Melts and Turns to Blood.
The Karaoke staff call her "the lonely girl." She rents a room all night and won't go home. Why? And what can Nogami say to help her?

2) Suicide Note.
Two charming girls, Michi and Rina, decide to end their lives this day. As the day ends we slowly discover why: both the horror--and the hope.

3) White.
It happened once, years ago... Now it's all Minako can think about. She yearns to do it again. But how does her brother feel...?

4) Yellow.
She just wants her brother to look at her--really look at her as a girl, not just a sister.

5) Blue.
They were finally reunited after their parents divorced. She can't resist her feelings for him anymore. But will she lose everything for one night of bliss?

6) Prohibition.
A walk together. A stolen kiss. Tears.

7) Moon River.
A young man studies and studies while being afraid of his own problems of failing. Until he meets a girl with a specific problem of her own by the river...

8) Bitter Cakes.
Miho meets with her friend Natsuki, who is blind. Natsuki trusts her other senses--and herself. But Miho trusts no one--yet perhaps trusts her eyes a little too much...

9) Love Horizon.
A girl sees her high school crush by chance, but something is very different about him.

10) The Day It Rained.
A short political piece regarding a young man, and a doll.

11) No Count.
A young girl finds out that her first kiss was with her oniichan.

Makoto Niwa moves to live in the city and meets his first cousin Erio Touwa at the house of his aunt Meme Touwa. Erio is no longer enrolled on the register of the school and is constantly wrapped in a futon. Erio claims that she is an extraterrestrial life.

From Hochuuami:

Four-eyed Nobita is ignored by everyone at school or they highly suspect he's an anime dork. Little does he know, sexy Ritsu has been staring at him from afar. What happens when the glasses come off and what's next... the shirts?

Note: The story is unfinished because the mangaka passed away.

Republic of Biscotti faces a predicament by the invasion of Galette Leo Knights. In order to save the country, Princess Milchore summons a "hero" from the outer world. Shinku, a junior high school boy living in the Earth, is chosen as the hero.

*This series contain side stories to the anime series that take place before the series, in between some episodes and at the end.*

Du Ming, young anesthetist in a big Chinese hospital, is haunted by the memory of Zhang Qian: a young lady coming from the same school as him , who bewitched him by the sulphurous beauty and the aura of strangeness she emits. After graduating, Du Ming stayed in touch with Zhang Qian, who writes him. Now a terrible piece of news arises: the young lady is said to have committed suicide. From Manga-News.