A mysterious Japanese man, known only as "Zig," travels to the world's conflict areas and undertakes various jobs. When the story begins, he's working as a security guard at a bank that's suddenly taken over by terrorists.

"Akatsuki" is the first ray of light emerging from pure darkness. "Samson" Takaki is the ace wrestler and company president of the Akatsuki Pro Wrestling group. Samson has devoted his body and soul to his wrestling career. Now, Samson not only has to endure the bodily damages caused by his long wrestling career, but he has to face prostate cancer. However, this doesn't deter Samson. He continues his fight to bring joy and entertainment to his fans.

28 years earlier, there was a plane crash in the mountains of Gifu Prefecture. The barrier that the Kobo Daishi, Kukai had created to seal away the demons was destroyed in crimson flames... Present day, Oniwakamaru, King of the Yokai, appears inside the body of pure and innocent Tachibana Hitori!!

This is a side story of the Tough series based around Miyazawa Seiko (Kiichi's father) and his brother Kiryu. Many of the same elements of Tough can be found here, such as mixed martial arts and a lot of violence.

From MangaHelpers:
Art equals expression, an expression creating an outer form, expressing joy, sorrow, and the darkness of the soul. Yutou Riro is a student at an art college, but she believes she lacks the talent to truly succeed as an artist. Entering her life through a series of coincidences is Karaba Jo. To Riro's astonishment, Jo has an exceptional ability to draw the "real" self of the people/object he draws. His artwork draws attention to the finest details of his subject, bringing to light the truth behind each individual.

From Viz:

Nobody enjoys a good fight more than "Kiibo" Miyazawa, a high-school student whose father is training him in the family's secret martial art. Kiibo dreams of becoming the next Bruce Lee, but his awesome fighting skills may soon surpass his idol's!

When an American scientist carrying a cure for the AIDS virus is kidnapped by an arms merchant, John Kyosuke is forced back from retirement. He accepts the challenge to regain posession of the anti-serum. He finds out that some of the people he is after are closely related, which gives his conquest a whole new meaning...

Volume 1 includes the oneshot that would eventually lead to the series Damned.

This is a no-holds-barred story about an ex-biker gang leader turned cop, Kenji Date. Operating under the nickname Hyena, Date rubs pretty much everybody within the police force the wrong way as he goes about his business ridding the city of all its scum.

Bad Police also contains two separate short stories at the end of the volume:

Bomber

The Chinese leader, Deng Xiaoping, had promised to rid Hong Kong of its criminal organizations. One of the places they migrated to was Japan. Kamon Shou is a delinquent who just got released from Youth Detention after spending two years there and is about to feel first-hand the effect the Hong Kong mob has on Japan.

Artemis

Ginko is a detective working for the famed Holmes Detective Agency, an agency that takes on the most dangerous of jobs: ones that even the police wouldn't even think about doing. She gets hired by Ms. Nancy to retrieve her seven year-old son, Tom. Tom was taken away by her father-in-law's mafia organization in hopes of cultivating Tom to become the next leader.

M60-toting Kenji Hado, known as "the Hard", pays his divorce bills by working in the US as a bounty hunter. Masseria, a ruthless and ambitious mafia boss, targets his family - starting with the Hard's father-in-law, a Don in the NY mafia. Hard's aim, while poor when sober, becomes extremely accurate when drunk!

Note: The short story N.Y. Dust, in volume 12 of Riki-Oh, was the prototype for The Hard.

The story is set in a dystopian near future where the Japan society is experiencing a crime rampage and in which a powerful and secret religious organization, with mysterious goals, is acting as an invisible hand behind the scenes.

The main character is their strongest assassin, lent to them by his fanatic mother when he was a child, and now a ruthless killing machine whose fists and feet cause serious damage to his adversaries, and whose weapon of choice is a special cutting wire with which he grabs and scorches his opponents.

He's a man hunter, whose childhood has been stolen and molded after his tormentors, but when the road of forgiveness is precluded to him what can be left to a man to obtain the redemption?

Takeo finds the answer in the vengeance, and in eradicating that same evil from which he has born.

So this dark and impressive badass guy, after betraying the sect, gets down to business kicking their ass and unleashing his fury against the deadly opponents sent to stop his unparalleled revenge.

This is a mixed martial arts fighting manga about the Miyazawa school of martial arts. Initially, it is about Kiichi trying to heal his father after he was nearly killed by his brother Kiryu. But then it goes on to be less about that as his father recovers and some tournament style fighting begins. At that point various apparently overwhelming opponents will encounter Kiichi on his way to the top. The objectives of the various characters start to play a more and more important role, as well as the different philosophical projections of several martial arts and disciplines. (Somewhat maybe like a modern day Samurai story.)

This is also a continuation of Koukou Tekkenden Tough which followed the main character, Kiichi, when he was younger and was training under his father Seiko Miyazawa. (Knowing the prequel isn't necessary at all.)