Majinga Z

An autobiographical manga focusing on the creation of Great Mazinger.

A retelling of the origins of Mazinger Z.

This book is one of a series of anthology comics published by Futabasha related to the long running Super Robot Wars series. 

Five different artists contribute a one-shot story:
1. Half God (Ashura) by Tomoshige Ishikawa
2. Rocket! Rocket! Punch punch punch!! by Takayuki Sakai
3. Great War of UFO Robot by Masahiro Fujii
4. Iron Cross Corps vs Mazin-Girls by Shinpei Ito
5. The last Space-Thunder by Tetsuya Kawaishi and Dynamic Production.

The autobiographical manga will reveal the untold story of the creation of Nagai's Mazinger Z mecha manga. 

(Source: Anime News Network)

New Isekai inspired Mazinger serie by Dino Getter's Kazumi Hoshi.

Mazinger Z is an alternate telling manga made in collaboration with Gosaku Ōta and Go Nagai, compared to the original and TV Magazine manga by Nagai, this manga was made more in tune with the anime while adding its own original elements. 

The manga focuses on a plot more similar to the anime starting with Koji checking on his grandfather after Baron Ashura had activated a bomb. With his dying breath, Dr. Kabuto gives Koji the Super Robot Mazinger Z. With the threat of Dr. Hell looming, Koji fights against his Mechanical Beasts and lieutenants with help from Sayaka Yumi and to some degree Boss.

MazinSaga is a manga written and produced by Go Nagai between 1990 and 1998; currently on going again, it's the summa of Nagai's works, for the complexity of the plot and the treated thematic content.
Mazinsaga tells the story of the young Koji Kabuto, university student who finds himself having to collect the fruit of the researches of his father, physicist of world-wide reputation who died in mysterious circumstances.
The boy is thus given a powerful artefact, Mazinger Z, the Armor of God.

A retelling of Mazinger Z mixed with ancient Greek mythology with a modern touch.

An alternative take on Mazinger Z, in the future, the world was destroyed by the demon know as Mazinger Z and the only human that is left on earth is Kouji Kabuto, he is given the chances to save humanity, by sending him back in time by a mysterious Minerva X, in this take the history is for adults, with nudity and blood that may be too much for some fans of the original version.

A remake of the original Mazinger Z manga in celebration of its 50th anniversary. This manga is the in-universe story of the manga that Gekiman creates in the autobiography manga Gekiman! - Mazinger Z Chapter

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. 

*Note: This part of Gekiman! mostly focuses on Devilman.*