Prior to the OVA, a manga titled Mazinkaiser SKL Versus was published in the mobile phone magazine Shu 2 Comic Gekkin. The novel adaptation was serialized in ASCII Media Works' Dengeki Hobby Magazine. Like Mazinger Edition Z: The Impact!, this series is influenced by other works by Go Nagai including Devilman and Violence Jack.
Set on Machine Island, an island that during a great war, it was isolated from the rest of the world after an experiment by WSO went wrong. Three factions - the Garan Army, the Kiba Army, and the Hachiryokaku Army - have taken over the island and now fight for total dominance of Machine Island and its resources.
To assure total quarantine of the inmates, the WSO created a gravity curtain to keep people in and out. Currently, each faction controls a part of the machine that powers the gravity curtain. The only way through the curtain is with machines created by the WSO.
However, each faction developed its own machines from the remains of defeated WSO machines and the vast resources found on the island, like the GRK-7 and the DBM-2.
Each faction is led by a unique personality: the Kiba Army is led by a psychopath called Kiba, the Garan Army is led by the warlord Garan who resembles a samurai, and the Hachiryokaku is led by the peaceful Aila.
One day the WSO learns the gravity curtain has become unstable and will explode in 66 hours, destroying the planet and all life along with it. Quickly, the WSO sends the Skull Force in to combat the each faction, reclaim each of the gravity curtain machine's parts and end the crisis.The Skull Force are made of two teams: the two-man Death Caprice Squad consisting of Ken Kaido and Ryo Magami, who together pilot the super robot Mazinkaiser SKL, and their backup the Gren Falcon Squad. When Skull Force enter Machine Island, the Gren Falcon Squad are decimated, leaving a single survivor, Tsubasa Yuki, as the only backup for the Death Caprice Squad.
From here on, the remaining Skull Force battle through three armies to power down the gravity curtain before it explodes and destroys the Earth.
- In the scanning of Iron Kaiser in the database, freeze framing reveals Mechanical Beasts.
- The voice actors of the main characters later voiced Devilman characters in the crossover Cyborg 009 vs. Devilman.
- Kaido is voiced by Shintaro Asanuma who voiced Akira Fudo.
- Magami is voiced by Satoshi Hino who voiced Ryo Asuka.
- Ironically, Kaido and Magami's code names match up with the above character's alter-egos.
- Tsubasa is voiced by Saori Hayami who voices Miki Makimura.