Mazinkaiser SKL was a 3-episode OVA series based on the Mazinger Z mythos, released over a period between January 28th and March 25th of 2011. It's directed by Jun Kawagoe, director of New Getter Robo and Super Robot Wars Original Generation - The Animation (OVA).Three Armies, led by Garan, Kiba and Aira, occupy an island hidden under a Gravity Curtain and fight to seize control over it. When the world government of WSO finds out that in next sixty-six hours the Gravity Curtain is going to overload and blow up the entire planet, they send the Skull Force - a special team of Super Robot pilots - to destroy three devices mantaining it. Among them are Ken "Amon-6" Kaido and Ryo "Lucifer-4" Magami, pilots of Mazinkaiser SKL.A novelization of it has been already released, along with a Manga adaptation.
This OVA has examples: