Andy Hinomiya. The former investigator has gone on a vague journey. Where will his wanderings take him, and what does he hope to achieve? What does the light beyond the end reflect in his left eye? Unlimited. There are sins (original sin) that only darkness can judge.

From MangaHelpers:

High-school girl Yui found a mysterious boy lying unconscious on the beach. This mysterious boy can't remember where he is from, only that his name is "Sid." After a confrontation with the locals, they discover that Sid is one of the human weaponry developed by the Japanese government, known as "Uncanny Brains" or UB. As the powers of the UB unfold before them, will Sid's arrival on this island spell doom for Yui and her friends?

Oneshot by the author of Murcielago about a high-school arms dealer and a sale that goes horribly wrong. Comedy, absurdity and violence ensue.

For years, fans of the animated series (Avatar: The Last Airbender and The Legend of Korra) have been burned with one question - Wwhat happened to Zuko's mother? Finding a clue at last, Fire Lord Zuko enlists the aid of Team Avatar - and the most unlikely ally of all - to help uncover the biggest secret of his life.
An Earth Kingdom Scholar's points of view about "family" and governing with dignity motivates Zuko to set things right within his own family. He makes a deal with Azula, releasing her from the mental institution in exchange for her help on his quest to discover the truth about their mother, Ursa. Additionally, with the help of Aang, Sokka, and Katara, the five set out on a journey towards Ursa's hometown. Tensions between Azula and the rest stir trouble and an encounter with a wolf spirit delays them even more, though as they continue, they find their own dynamic to make it all work.

When Tokyo ESP meets Ga-rei...

From Kodansha Comics:
In the gritty, futuristic city of Neo-Saitama, the streets run slick with acid rain and blood. Here, an army of cybernetics-clad ninjas runs amok under the menacing rule of the Soukai Syndicate. As incessant strife wrought by a ninja turf war takes the lives of all citizens who end up in the crossfire, one can only hope to end the day without getting a suriken to the skull. But in these dark, tragic times, a spirit of vengeance rises to kill all wicked Ninja who terrorize Neo-Saitama. This crimson avenger is Ninja Slayer, and he will not rest until all Ninja have been slaughtered at his hands.

Since long ago, a bitter rivalry and feud has long existed between two clans, the Toujo and Toyoda families. Because of this feud, it has long been Kanade's job as a shinobi to ensure the safety of Keigo, a member of the Toujo family, ever since childhood. Her devotion to her duty as a guard is a source of contention for Keigo, who would rather have her as a childhood friend than as a protector.

Of course, this protection extends all the way to school, so when Kanade comes across the Eishi Toyoda in class, the heir to the Toyoda family, she is initially hostile. After an attack, Kanade soon discovers Eishi is not exactly who she expected, and that threats to Keigo's safety do not just exist from the Toyoda family but within the Toujo family itself.

A power struggle begins in a civilization dependant on an ancient technology, the blastia, and the Empire that controls it. The fates of two friends traveling separate paths intertwine in an epic adventure that threatens the existence of all. (Based off of the RPG for the Xbox360 and PS3)

Saving the life of the girl he loves, Sahu incidentally turns into a zombie. And now he's trying to survive in a stone jungle, believing that one day he will sing for the world.

After being reformed by the GTO, Eikichi Onizuka, the Twins of Terror, Riko and Miko Sakaki, leave their past behind and become members of the Disciplinary Committee at their school, Chigasaki Kahoku Private Academy, helping fellow students in need through an SOS messaging system. When an illegal prostitution auction ring is uncovered at their school, the twins set out to restore peace to their school and punish those responsible.

Following the first year high school student, Arisugawa Hikaru, comes a tale of Gaitou: a thief who only appears in dreams and steals the darkness inside of people's hearts. Hikaru, one of the Gaitou, hunts down Gai rabbits, one of the lower-class demons that seek the darkness in humans. With the aid of his companion, Ban, Hikaru protects people from falling into despair, however, the game has yet to begin.

What can you do when you get mistaken for murder? Nothing. You go to prison. Lucky for you, your inmates are some of the biggest cutthroats in the prison. Seriously, you are lucky. Especially when zombies attack.

The Empire of Britannia invaded Japan using giant robot weapons called Knightmare Frames. Japan was reduced to Area 11, an imperial colony, and its people referred to as the Elevens. At the time, Lelouch, a young Britannian boy exiled to Japan, vowed to his Japanese friend Suzaku that he would destroy Britannia. Years later, Lelouch is a high school student who regularly skips school to play chess and gamble. When he stumbles on a terrorist group of Elevens who are caught by a Britannian task force after stealing a military secret, Lelouch is unexpectedly reunited with Suzaku, who works as a member of the Britannian military. As the rest of the task force arrives, Suzaku is shot for disobeying orders, while the military secret, a young girl, gives Lelouch the power to make anyone obey any order. Taking command of the terrorists, Lelouch adopts the alias "Zero" and begins his rebellion to crush Britannia once and for all. However, his greatest friend soon becomes one of his most troubling enemies when Suzaku becomes the pilot of Britannia's new test model Knightmare, the Lancelot. Note: Storyline is a bit different than the anime.

Neo Universe was an online game that was very popular in the story. Ganda participated the game, hoping to become a GM like his brother Vissana. Unfortunately, Ganda was tricked by an Anti-GM member named Waipoj, and Ganda accidentally became one of the Anti-GM members.

From Batoto: For a long time, wars have been waged between the Overworld and Underworld. In order to end this, people fought for their own cause.

The "battle fantasy" series takes place in a university town by the open waters of Tokyo Bay. In the story, the enemies of mankind are known as "angels" and the school's students train to fight the angels.

Old Gods are invading Earth, possessing humans and baring naked their most wicked emotions. The most powerful 'disciples' of these evil demons are called 'mages'. The story concentrates on two such people: Yoguruma Mugen (disciple of Yogusutoosu) and Narukami Chikage (bound to Nyarlathotep). Their strained relationship and addition of another, seemingly human girl thrusts us into the world where no black or white exist. In this strange and brutal world fight to stay human even in the worst circumstances continues.

The author seems to use lore from the Lovecraftian mythos.

About the title, ダイン (roomaji: dain) is Japanese for dyne, which has the symbol or standard abbreviation of dyn. It is a unit of force that was used in physics starting in the mid-1800s but was largely supplanted by later systems.

See:
http://en.wikipedia.org/wiki/Dyne
http://ja.wikipedia.org/wiki/ダイン

Shitou Teruaki is a former top-notch bounty hunter who's been out of the business for a while and is currently struggling to get back in the game. He takes up a relatively low-paying mission to track down a serial rapist because of his desperate need for money, and is surprised when the currently 2nd-ranked bounty hunter -- the mysterious and assertive "K" -- appears to be competing with him for the prize. But when Shitou encounters local Ice Prince Ayatsuji Kaoru by "saving" him from the clutches of said rapist, the battle for being the #1 bounty hunter really starts to heat up...

manga sequel to K project movie, Missing Kings.