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.

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)

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)

Slight retelling of the 2001-2002 Mazinkaiser OVA series.

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)

This series is a complete remake of the original Mao Dante, with new designs an a story slightly inspired by the anime of 2002. This time, the story spans longer, the character design is different, and all unanswered questions left when the original series was interrupted, are responded. This time, Mao Dante has a proper ending.
The story is divided in four parts: Kami Ryaku Hen, Gen Ma Hen, Mado Hen and Kami Ma Taisen Hen. (mangaupdates.com)

A tale of a young hero on a magical journey!

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

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)

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!