Continuation of the successful manga and anime series Mazinger Z, Great Mazinger starts after the defeat of Mazinger Z. Tetsuya Tsurugi is the new protagonist, piloting the powerful Great Mazinger, a creation of the once thought dead Kenzo Kabuto, the father of Koji Kabuto. This time the enemy is the Mycene Empire and its powerful robots. (manga updates)

A Violence Jack one-shot from 2001. What happens when Jack and some bikers mysteriously get sent back into the age of samurai.

A tale of a young hero on a magical journey!

The archangel Micheal gave King Solomon a ring with the name of God inscribed on it. Using this ring Salomon enslaved 72 demons and used them to build his kingdom when finished he sealed them in an urn and cast it into a lake. 3000 years later the ring of Solomon is in the possession of a young Tokyo girl named Miki who believes herself a witch.

Welcome to the Sparta Acadamy, run by a head master called Satan's Toenail. If you get anything below a 90 on every test, they punish you with torturous devices and the like. But fear not, there is one who stands up to this great injustice, in nothing but a mask and high boots. That's right, a naked fighter of Justice, Kekkou Kamen is here to punish the unfair system of the Sparta Acadamy and bring justice to those who study too much!

Mazinger Angels chronicles the adventures of four women who pilot giant robots in the Mazinger vein. The concept is a spoof on the late 70's and early 80's popular TV series Charlie's Angels.
Three of the robots, Aphrodite A, Diana A and Minerva X are from the original Mazinger Z series, while Venus A is from the Great Mazinger series. Their pilots are also traditional characters from Go Nagai's universe, Sayaka Yumi and Jun Hono from Mazinger Z and Great Mazinger respectively, and Hikaru Makiba and Maria Fleed from Grendizer.
The style of the manga highlights the sex appeal of both the characters and the mechas, sometimes similarly to the way Aika's female characters are shown.
(Source: Wikipedia)

Akira Fudo, who has become the Devilman, the only being who can fight demons; a being possessing the powers of a demon and a soul of a man.

A long time ago, the Earth was ruled by demons. The demons constantly fought each other for survival, but soon found themselves fighting a new race of beings: The first humans. The demons then became imprisoned in ice after a great cataclysm. They would remain there until the ice melted, after which it was said Satan would rise and lead them in Armageddon. That time has come in Go Nagai's Devilman.
source wikipedia

Slight retelling of the 2001-2002 Mazinkaiser OVA series.

It is 199X A.D. In Kushiro, Hokkaido, three bodies of Dragonite appear. Possessing overwhelming destructive force, they attack the city. They also awaken the evil Jashin Drago from the holy seal he was trapped in. 200 years ago, Drago was trapped in the seal by a holy warrior with the tattooed mark of the Liger. Assuming that the warrior is dead, Drago and Empress Zara are free to conquer the Earth using their army of biomechanical beasts. Even the Japan Self-Defense Forces are no match for the Dragonites' awesome power. One of the people fleeing is the protagonist, a milquetoast 16 year old boy named Ken Taiga. Unbeknownst to the Dragonites, Ken realizes that he is the descendant of the Liger warrior. In a burst of anger, Ken's Liger birthmark appears, and he rises his palm into the air, shouting the henshin command, "LIGER!" which then covers him in demonic, long-haired biomechanical armor. Ken transforms into Jushin Liger to fight the evil forces of the Dragonite!
(Source: Wikipedia)

Join a group of street beggars on their wacky and insane adventures.

Jun's 18th birthday has been selected by family tradition to be the day that her husband is chosen. Many high-class families have come to try to marry into the physically and economically powerful Asuka dynasty, but Jun is not interested. With her servant Kratta in tow, she runs away from the groom-choosing party.

One of Go Nagai's first works, this violent period piece takes place in the 1500s and stars a talented low ranking ninja named Shishimaru. In it, Shishimaru fights against Ginnai Doma (an immortal samurai who, despite being butchered multiple times, doesn't die) because Ginnai murdered his comrades. Despite being set in historical times, it has machine guns/lasers/robots/atomic reactors with no real explaination.
(Source: MU)

A story where students face off against teachers to bring down the tyrannical education system.
(Source: MU)

Fudo Jun is a school teacher having dreams of uncontrollable urges of violence. She takes the school tennis team on a trip where they are attacked by demons. To try and save the girls and herself she ends up unleashing Devilman Lady.

Mazinger, later called Mazinger U.S.A. Version or Mazinger U.S. Version to avoid confusions with the rest of the Mazinger works, is a 58 pages long manga created by Go Nagai specifically for the US market. It features full-color graphics, text in English and left-to-right formatting. It is partially inspired by Gulliver's Travels.

The year is 2005. The police, unable to carry out their work, are asking for help from talented private investigators for the most complex and important work.
Among these are Seiko Hayami, who, with the help of her assistant Hisashi Hanyu, will be involved in cases concerning strange apparitions of monstrous beings, which will eventually lead to a confrontation with the Panther Claw terrorist organization/religious sect, who worship the goddess Zora, under the command of the bestial Sister Jill.
Defeating the organization seems impossible, but help is at hand from the android, Cutie Honey. Having seemingly traveled from the 70s to defeat Panther Claw, she resides with Seiko in the form of Hisashi. (Source: Wikipedia)