An autobiographical manga about the career of Nagai Go and how his most known works were born.
How a young Nagai Go, struggling to break out of his typecasting as the go-to guy for gag manga by breaking into the sophisticated world of story manga.

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)

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)

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.

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

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)

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 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.

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. 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)

The great demon Mao Dante, exploiting the weakness of a boy exposed to his demoniac influence in the dreams, is awakened from a thousand years sleep.
The will of this being, a survivor of an ancient and forgotten civilization , is to wipe out the whole human race.
Anyhow nothing is so simple: the motivations of the demon aren't so wicked as one could think and they will combine with the life of the boy which hangs between nightmare and craziness.
In the meanwhile the satanist will fight against the hierarchy of the church to obtain a justice which is, as it's easy to guess, that of the demon Mao.
This series didn't have an ending until it's remake in 2002. Nagai took many ideas from Mao Dante into Devilman. (mangaupdates.com)

Slight retelling of the 2001-2002 Mazinkaiser OVA series.

A kid hears a voice and suddenly finds himself in the company of a demon!

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.

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

After the world ended in the original Devilman, Akira Fudo is in hell, seeking the soul of his beloved Miki while at the same time Doctor Hell is beseeching the underworld for power in order to get his revenge upon the hated Mazinger. Akira sets in motion a chain of events that earn the enmity of Hades himself, who'll stop at nothing to avenge the slights Akira commits against him...