From MangaHelpers: Tatsuo, Hide, Satoshi and Aya worked together to cheat people out of money. They tended to target marriage services, where they con money out of people looking for love. They were good at it, until they crossed the wrong guy. Then they saw the world below the surface of dupes to cheat, when the 'collection agency' came for them with extreme violence. The person who takes Satoshi and Hide, and then Aya and Tatsuo, is a wild-eyed maniac who seems to get off on the torture. There may be hope for Tatsuo, though, because the man recognizes him. The torturer is "Akasada" a bullied kid that Tatsuo knew from school. Now Tatsuo and Aya have been pulled, against their will, into Aka's world. [tethysdust]
Yuta Ono, a failed contender, was unable to gain admittance to the university of his dreams in Tokyo where his high school sweetheart, Minori Tajima, was enrolled. Consequently, he was forced to become a ronin. Disagreements with his father over the family business led Ono to a dilemma where he had to move out with only 10,000 yen. Luckily, he chanced upon Nutopia, a rental house in search of a male tenant. However, Ono was in for a surprise as he discovered that the house was occupied by five pretty girls between the ages of 20 and 30. This predicament was particularly daunting considering his girlfriend situation with whom he hadn't broken up yet, posing a significant distraction to his life as a ronin.
Set 16 years after the "Law for Public Order and Morals in Healthy Child-Raising" banned coarse language in the country. Tanukichi Okuma enrolls in the country's leading elite public morals school and is soon invited into the Anti-Societal Organization (SOX) by its founder, Ayame Kajō. As a member blackmailed into joining by Ayame, Tanukichi ends up taking part in obscene acts of terrorism against the talented student council president Anna (for whom Tanukichi has a crush).
From etc: Based on historical setting of Korea during the Josun Age. Long ago, in Jushin, secret royal inspectors named "Angyo Onshi" wandered the country and restored the order. But now that Jushin is destroyed, only one is still wandering...
A continuation of Say Hello to Black Jack, published by Shogakukan instead of Kodansha.
Ryo and Akira travel through time in order to eradicate demons that could have changed history. Various periods are visited: from pre-WWII to ancient Greece, middle ages in France meeting Joan of Arc, far-west America, renaissance.
From Wiki: Sensoron is a controversial series of manga written by right-wing Japanese manga artist Yoshinori Kobayashi.
In the near future, a mineral known as "Japanium" is discovered under Mt. Fuji. This ore is discovered to produce a powerful energy source known as "Photon Energy". Dr. Juzo Kabuto and his associates have begun researching Photon Energy, planning to use it as a solution to the energy crisis plaguing the earth, when the nefarious Dr. Hell and his associate, Baron Ashura attack his lab. Along with this, the mysterious "Kurogane House" also has begun to become entwined with the affairs of these two parties. During all of this, Juzo's grandchildren, Kouji and Shiro, encounter one of Baron Ashura's robots on its way to attack Dr. Kabuto's mansion, where he has begun work on his greatest invention. Dr. Kabuto, seeing the danger at hand, sends out the Pilder to Kouji, allowing him to combine with the giant robot, Mazinger Z, to fight against Dr. Hell's forces.
Six months ago, Karukozaka High School was sucked into the demon world, and in the ensuing chaos, only two survivors emerged: Nobu, who defeated the Demon Lord that took over the school, and Yumi, who possesses latent demon powers of her own. Although they're both trying to put the incident behind them, the gateway to the Underworld remains open, and soon Nobu finds himself battling demons right on the streets of Tokyo. The reason for this infestation is simple: a secret organization is trying to establish a Demon Kingdom on Earth by summoning demons through the gateway. Nobu and Yumi are the only people to have been to the Underworld and survived, so they may have the power to stop the infestation but before that can even happen, they'll have to find each other first.
The story is set in Japan a millennium from now. Five children — the protagonist Saki, Satoru, Maria, Mamoru, and Shun — have been born and raised in a tranquil town that can be described as a utopia, overflowing with water and green foilage. The world is ruled by people who have the "cursed power" or the "gods' power" of telekinesis. After a certain incident, Saki and the others come to realize the true nature of their world. Before long, they learn everything, including the bloody history that brought humanity to this state. The five throw themselves into life-threatening adventure and fighting to protect friends and a world on the brink of collapse.
This brief resurrection of Go Nagai's Violence Jack character appeared in 8 chapters in the magazine Comic Bunch in 2005 and has never been collected in a single volume. OK, resurrection may be the wrong word since Jack didn't actually die when Nagai ended the original series in 1990 and he also didn't bite it in the 2001 stand-alone short story DEMONS IN A WAR-TORN land. But you get the idea. (Taken from deadfrog.us) The serializing resumed in 2007 and is still being published in 2008.
Yukie grows up in the countryside in the 1930s as a daughter of a well-off family plagued with dark secrets. Surrounded by people but without any real friends, she tries to come to terms with herself and learn what love is.