Mazinger Z: Alter Ignition

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.

After being warped from their universe to that of Mazinger, the Transformers join the fight between Mazinger Z and Dr. Hell's army of mechanical beasts. A crossover between Mazinger Z and the Transformers series, with each chapter drawn by a different artist.