Continuing the October Fest, we have our first of the Mazinger Monsters, Skeleton O7, a Mechanical Monster first featured on Episode 68 of the original Mazinger Anime, which first featured the Agent of the Mikene Empire Archduke Gorgon, and saw the introduction of the first Ghost Mechanical Beast, Gusios βIII (Beta 3), tho the two Monsters didn't fought side by side in the episode. Skeleton O7 resembled a Skeleton Gorilla, with a big Red color upper chest covered with bones with purple shoulders and a short brown pelvis, his skeleton arms were longer than his skeleton legs and the skull was more gorilla than human like and wore a red helmet, with yellow rivets on top. He had the ability to fly thanks to a rocket pack and his primary weapon was an Ultrasonic Screech which disoriented his opponents and crumbled buildings. His Bone armor was resistant to projectiles, and like Belgas V5, he could dismember and then reassemble himself as a deception tactic.

Going through a mental and emotional meltdown, Dr. Hell goes on rampage, destroying unused mechanical beasts, viewing them and himself as a failure after his past creations where defeat one by one by Koji and Z, he is stopped by both Brocken and Ashura, who Dr. Hell also puts blame on for the past failures. Seeing his master in such distraught state, Count Broken takes Skeleton O7 on the Gool and leaves for battle, as Dr. Hell expresses doubt of his endeavor. Gool is detected and Koji and Mazinger are dispatched for a fight and Skeleton is launched, and when Koji sees it, fires a rocket punch, tearing it to “easily” to pieces. Concern about how easy this job felt, Koji suggest to pick up the pieces and Sayaka and Borot are dispatch to pick what's left of the beast, as Brocken watches, all going according to plan.

As Ashura reproaches Brocken, he/she is recall by Dr. Hell and orders Ashura to sail to the Naruto straight, to find Archduke Gorgon, as the Military forces of the Mikene Empire are amazing there as the first advance force. Ashura begs the Dr. Hell to reconsider as Brocken's mission is still on going, but the decision is final and gives Ashura a letter written by him to the Archduke, and takes off to its destination on the Bood. As Ashura reaches the straight the Bood is caught in a whirlpool and its suck into an underwater base, where he/she presents itself to Archduke Gorgon and delivers the letter.

Meanwhile, in the Photon Power lab, the remains of Skeleton O7 is stored in one of the hangars, while the pilots act in contempt to the situation, a concern Prof. Yumi orders test on the remain, which come out negative, when at that moment the Gool is detected and once again, Z is dispatched. Having force Z out, Brocken orders Skeleton into action while he and the Gool fight, the beast reassembles itself and attacks the lab, Borot and Aphrodite are dispatched, but the Beast's Sonic screech knocks Boss, and Aphrodite's Rockets prove ineffective. With success in sight, Brocken reports to Dr. Hell of the impending success only to be told to expect re-reinforcements from the Archduke Gorgon, leaving the count somewhat bewildered and ending the transmission.

At the underwater base, Gorgon laughs after reading the Doctor's letter and rips it apart, viewing it as an admission of ineptitude by him, Ashura is force to admit he/she came to seek his help in his/her master's name. Humored by the situation, Gorgon accepts and lends Gusios βIII, one of his Ghost Mechanical Beasts. Back with Z, he ram constantly by Gool in repeated suicidal runs, when he gets the called of problems on the lab. Koji dispatches it with a Rocket punch which forces the Gool to retreat and Mazinger flies back to the lab. Koji tries to use the rocket punches, but these make no dent on the monster, and all other attacks prove ineffective, as with every hit, Skeleton breaks up and reassembles. The Beast latches on to Z and blast its Sonic Screech, which harms Koji, losing control and crashes. As the beast beats down on the cockpit, Borot and Aphrodite wake up and provide assistance, when Brocken learns of Gusios' appearance at sea, making the Count distraught with the thought the Doctor no longer have any faith in him and orders Skeleton to go berserk, which it does, and fights with greater fury, causing more damage. Z rips the head off with the iron cutter, and attempts to finish off the body, but this explodes. Koji and Yumi are left wondering why Dr. Hell sent such an unsophisticated Beast, unbeknownst to the incoming reality of a new and powerful foe.