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.
(Source: deadfrog)

One of the first Super Robot manga and the one that introduced most of the traits of the Mecha genre. Constructed with the Super-Alloy Z, Mazinger was built by Professor Juzo Kabuto as a weapon against the Mechanical Beasts of the evil Dr. Hell. Koji Kabuto, the grandson of Professor Kabuto, becomes the pilot of Mazinger Z when his grandfather is killed, and battles from there on against Dr. Hell and his allies. This is the first series that introduced the concept of a pilot inside a Mecha, which all series from then on have followed.

Great Mazinger (Sequel)
Mazinger Angel (Alternate Story)
Shin Mazinger Zero (Alternate Story)
UFO Robo Grendizer (Sequel)
Z Mazinger (Alternate Story)

Spring, 1991. Mysterious gold metal balls fall from space... The balls were too small to be sensed by humans, so they were scattered across the entire earth without incident!

Included one-shot:
Zipang

Mazinger Otome depicts the mechas of the Mazinger franchise and Steel Jeeg series as androids where they fit into regular life. It follows the android girls that make up the cast as they deal with life in high school and from the school delinquents the Mechanical Beast Army. The main protagonist is Seto Magami, an android based on the Mazinger Z who is treated as the granddaughter of Juzo Magami. Later with the introduction of the New Mazinger Army, there are heated arguments and fights between them and the originals.

(Source: Mazinger Wikia)

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!

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)

Set in 2025, a roboticist named Fudou Yuuki joins a project involving a large mural depicting humanity's true past as well as the ancient but advanced technology found in Antarctica.

(Source: Devilman Wikia)

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)

Slight retelling of the 2001-2002 Mazinkaiser OVA series. Included in this vokume is a short story called Mazin Kaiser: Shin Majin Densetsu (Mazin Kaiser: Legend of a New Demon God).

Great Mazinger (Adapted From)
Mazinger Z (Adapted From)

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

Honey Kisaragi is a normal catholic schoolgirl. That is, until her father was murdered by the Panther Claws who were seeking the Airbourne Elemental Fixation Device. She then finds out that she is actually an android created by him with the Airbourne Elemental Fixation Device within her. She is now trying to live a life as a normal schoolgirl and seeking revenge against Panther Claw.

In 2071, north pole ice have melted and the land has been submerged. Humanity survived but it's divided into two species: the true humans, those who live in underwater cities, and the Dugons, those who chose to undergo genetic modification to live in the sea. Both species go to war to survive as long as the Dugons consider the humans good to eat.

To defend against the Dugons, the city of Mari Ramelle builds a new kind of weapon, the mermaid robot, Salacia. Because of the small size of the the pilot cabin, the robot is piloted by a girl and a boy, both 13 years old: Marin Yuuki and Ushio Mizushiro. The fight for survival is hard, and during the manga, the city builds more mermaid robots.

(Source: MU)

Slight retelling of the 2001-2002 Mazinkaiser OVA series.

A shocking and violent look at a post apocalyptic future. Many different stories centre around an array of characters dealing with life in this desolate world. All the stories feature a huge man named Jack who is in an ongoing battle with a villain named Slum King.
(Source: ANN)Note: This is kanzenban version which consists of: 7 volumes (published by Kodansha) and 31 volumes (published by Nihon Bungeisha) merged into 18 volumes.

In this story, Nagai gets his folklore on with every chapter containing a lot on Buddhist lore or Japanese folklore. The prologue introduces us to Heaven, Incorporated, a company with a particular staff that hunts down all sorts of supernatural monsters and protects humanity from them.
(Source: MU)

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

In the prehistoric times when men were reptiles and the world was over-run with dinosaurs, humanity was threatened with war. The humans are fighting against the almighty Gor to return peace to their world.