Hundreds of millions of years ago, highly-advanced beings looking to make a planet for themselves purposefully tampered with Earth's natural processes in order to create multi-cellular life. Watching the planet's evolution closely, they continued to help life evolve further in the hopes of having actual civilization develop.
It's now 1996 in Seoul, where Hyesong, a high-school student, struggles with the usual problems of youth. The only unusual thing about him is that he's been having the same apocalyptic nightmare for an entire month; in the dream he is an great fighter and genius tactician who faces off against a seemingly-unbeatable foe.
Are these dreams not really dreams? Does he really have a role to play in the cosmic balance of the universe? And is the new girl in his class really just a normal student?

From back of book:

He-Sung has dreams of the Earth being destroyed by alien invaders! In these dreams he is a motorcycle-riding warrior, the last defense against the alien armada. By his side is a beautiful armor-clad girl with strange powers and futuristic weaponry. But these are just dreams, and they don't mean anything... right? That's what He-Sung thought... until his mystery dream girl appeared as a new student in his school! But if she is real... can the aliens be far behind?

The protagonist is your average, everyday, Korean school student. That is, if not for his obsession that aliens live on Earth disguised as humans.

Much to his surprise, he was right, the aliens play a game called "Avatar" where they take human form and live human lives. And because of a glitch he caused in their system, now his very life could be at risk.

Now he needs the protection of an Admin of the "Avatar game" or else he could very well die!

The "Dark Flower" is a sword of legend; a horrible legend of a gruesome slaughter three hundred years past. Lilia, a small girl from a village threatened by the bandit group whose leader has obtained this cursed weapon is now searching for help to save her city. Unfortunately, she is spotted by the bandits and can only run for her life. But, just as she is about to be caught, she runs into a young and seemingly weak traveller... is this coincidence? The Winner of the 14th Square Enix Manga prize.

From Tokyopop:

Daphne in the Brilliant Blue take place in a near future in which the remaining population lives in underwater cities, with waterways as streets. Years ago, while conducting underwater experiments, all contact with the surface was cut off. With the remaining human population now living underwater, The Deep Sea 9 Cities Association represent the last hope of mankind. Ai Mayuzumi is the daughter of the head of the research lab, and is an expert water jet bike driver. When the terrorist group Error, attacks the city, Ai becomes involved with the counter-terrorist group Stelnas, comprised of an all-female team, and led by a girl named Kei, and asks to join them. The group initially resists her efforts to join, but a surprising "gift" that Ai possesses, along with the way she handles herself during a kidnapping attempt, eventually sways the opinion of the members of Stelnas.

From Futari wa Pretty Anon:

Chino Houjo is just an ordinary high-school girl. But when her childhood friend Souma is suddenly attacked, she’s forced to purchase a ‘prince’ from the alternate dimension Albox to save his life. And now she’s got to go after the person who’s stolen Souma’s soul?!

A seminal history of Date Masamune. Yokoyama has a plain and matter of fact style for history without really trying to dramatize it.

The main protagonist is an Iga ninja named Saizou, who meets an Izumo priestess and protects her on her short journey to Sanada Yukimura. Sanada Yukimura is a powerful warlord in the Sengoku era. Sanada wants to gather 10 warriors, a party unrivaled in skill and power, to set his still secret plan into action.

This is an original story expanded from the STEINS;GATE game, and focusing on the heroine Amane Suzuha. In 2036, a monopoly on time machines has created world peace, but at the cost of human liberty.

Suzuha has followed in her late father's footsteps in fighting alongside the Valkyrie rebellion force to change the world. After the group fails on a major mission, Suzuha has almost no hope left. But then she discovers that her father left something for her: a time machine. Using this, maybe Suzuha will have the power to finally destroy this dystopian society and create a better present and future!

Sara Tanjuro just recently transferred to Mikagami Eruma's elementary school and have caused a major stir among the students. Tanjuro, knicknamed Satan, has been proposing his love to the girls left and right, something the shy Eruma would never think of doing. But Satan has a secret identity. He is a member of Michaela, a group of people who combine technology and exorcism to rid the world of angels that wreak havoc in society. As member number 666, Satan is an anti-angel specialist who has disguised the school supplies as weapons. He defeats supernatural beings with ease. Now if getting girls were that easy...

From MangaHelpers:

Natural selection has created a deadly new species known as "Eclipse," who are driven to eliminate humanity. A scientist called Kurusu Kenji headed an organization whose purpose was to fight these deadly creatures of bone. To this end, he created the "Osteon," Eclipse-like creatures that obey the commands of the human from whose DNA they are created. Now Kenji is gone, and his assistant Kidogawa Rokuko is attempting to recruit his estranged teenage son. Kurusu Akira wanted nothing to do with the father that he believed abandoned him, but attacks from Eclipse force him to accept his own Osteon from Rokuko. He slowly finds himself drawn into the organization, whose members expect him to take his father's place. Akira and his Osteon may have little interest in protecting humanity, but they are determined not to be beaten! [tethysdust]

Alternative world where Japanese culture kept its ground to this day and further. Protagonist, a female entertainer typical to Japanese traditional customs, finds herself swept into the world oh so familiar, and yet so different from the one she lived in so far.... a world where she has to fight to survive.

Fate/Zero takes place ten years before the events in Fate/Stay Night, detailing the Fourth Holy Grail War in Fuyuki City.

Sengawa's day job is as an accountant working for the police. But at night, he transforms into a ruthless assassin bringing death to anyone who deserves it. Those who have been wronged and whose grievances the police can't - or won't - listen to, turn to The Man With A Thousand Guns to avenge their suffering.

The year is 2028, location in New Koshigaya. A young boy, Isurugi Neru, lives in a poor family and is forced to quit school so that he can find his own way in life. Neru on the other hand, only thinks of one thing: to take revenge on Yagami, a classmate, who's especially gifted and has humiliated Neru numerous times.

Etou Kai may look like a squeaky-clean kid, but the Greater Kanto Narcotics Control Division's new investigator hides a violent alter ego and a dangerous past.

With his stoic partner Kurabayashi Hal, Kai is assigned to track down and stop the distribution of Dragon Speed, a dangerous new drug. But Ryuugen, the syndicate trafficking the drug, is almost impossible to infiltrate. Add street violence and a jurisdiction war with the Meguro Police into the mix, and it looks like Kai's in for some very long days at the office.

From Tokyopop:

Three years after the popular video game The World was shut down, Tokio Kuryuu cannot wait for The World R:X to come out. Unfortunately for him, he forgets to reserve a copy and finds himself with no access to the game. That is, until a mysterious new transfer student forces him into the game and makes him her servant.

G.U.+ follows the player Haseo, a powerful PKKer known as "The Terror of Death". Haseo is obsessed with an infamous PKer known only as "Tri-Edge" who attacked a close friend of his sometime in the past. The manga details Haseo's search for Tri-Edge, and his eventual inclusion in a mysterious group known as "G.U."


Back story of the ps2 game (same title)
In 2015 a fire at the main CC Corp. building resulted in the loss of a lot of data, and The World was forced to shut down. By splicing in data from what would have been another game, CC Corp was able to rebuild the game system. The next year, "The World R:2" was released, but many old players objected because they were unable to bring over their old characters. However, many new users were drawn in by the new style, and over 12 million copies were sold. Though not a match for the previous version's 20 million users, it became the top-selling netgame on the market." As a result of the new world, four major clans (Kestrel, Lunar Tree, Canard, and Raven) came to power. The clans actions shape 'The World', and most players end up taking one side or another during conflicts.

From MangaHelpers:

On his seventeenth birthday, Amamiya Kota was going to ask his classmate Misora Hiyori out. Tragically, he dies in a car accident but is given a second chance back in the living world on borrowed time. He gets entered into a competition called the 13 Game where other people like Kota who were supposed to die return back to the world and given an option: locate and kill 13 other players or suffer the fate of death. Each player is assigned to a handler, mysterious beings with special powers, who use them as if they were characters in a video game. Kota’s handler, Merume, explains that there are players like him all over the country, each with a unique ability that helps them kill, and Kota has to kill 13 players within 1 year. With his demon hands ability that was inspired from his hobby of magic tricks, Kota must unwillingly participate in this cruel game if he wants to live. [vyc]

Seducing the guests to make them pay the most, that is the job of a host. Takashi, currently the No. 1 host, is an apparent professional when it comes to being a host. Being a host isn't Takashi's only job. The Persona XII, guided by the stars are to preserve the balance of fate. The eyes on an assassin serves the guidance of the stars.

Satsuki Kakeru lost his sister by suicide and has been living a dull life ever since then. One day, he is transported into a bizarre world "Red Night" along with his friend Minase Yuka and six other classmates. In order to survive and escape from Red Night, they must defeat six black knights in order to return home.