Tranzor Z

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.

Note: the scanlation uses Kodansha version which altered the chapters order, includes TV Magazine chapters, some pages were altered(like redesigns for Sayaka, Professor Yumi and Brocken) and there's missing pages, the missing chapters of Shonen Jump serialization along with some TV Magazine chapters were moved to Great Mazinger volume 1.