When regular energon just wont do, you need Energon Z! This super-powered version of the Transformers' fuel was developed on planet Micro, and became a target of Violen Jiger and his Nine Great Demon Generals.
Zone story pages
When Energon Z was developed on Micro, it immediately became necessary to protect the new energy source. To accomplish this, the Autobots initiated the "Zone Project", reconstructing and reinforcing planet Micro and turning it into planet Zone.
Zone cartoon and comic
To fuel his conquest of the galaxy, Violen Jiger ordered the Nine Great Demon Generals to steal Energon Z from planet Zone, intending to fuse it with the power of the Zodiac and create the super-energy he required. Overlord, Menasor, Abominus and Bruticus attacked Zone and although they were met with resistance from the native Micromasters, Overlord was ultimately able to tear his way into the Zone Base and rip the Energon Z from its housing. The Generals subsequently escaped back into space with the power source in their clutches.
The capsule of Energon Z was handed off to the second group of Generals, who weaponized it by installing it within Trypticon's mouth, enabling the Saurian General to discharge its energy in beam form. This group of Generals proceeded to attack Earth and were pursued by Autobot Powered Masters Dai Atlas and Sonic Bomber. During the battle which followed, the Zodiac was uncovered and fell into Dai Atlas's hands. Trypticon got mad at this and used him Energon Z Beam to severely injure Sonic Bomber (he was aiming for Dai Atlas, but Sonic Bomber decided to be a hero and take the hit). As Trypticon advanced on Dai Atlas prepared to fire on him again, Dai Atlas held the Zodiac aloft and implored it to gift its power to the two Powered Masters, at which point Trypticon unleashed the Energon Z Beam. As the energies of the Energon Z washed over the Zodiac, its powers were awakened and caused Trypticon's beam to have no effect, and Dai Atlas and Sonic Bomber were able to transform into powerful "Zone Modes." They used their enhanced firepower to wipe the Generals out, but it was unclear if the Energon Z was destroyed in the resulting blast, or if it survived to be salvaged from Trypticon's remains.