Mazinkaizer SKL (マジンカイザースカル, Majinkaizā Sukaru) is a Japanese OVA sequel to Go Nagai's Mazinkaiser, which was in itself a spinoff of Mazinger Z. The first episode of the OVA was first screened on November 27, 2010 (2010-11-27), and was released on January 28, 2011 (2011-01-28) . It also has a novel adaptation serialized in ASCII Media Works' Dengeki Hobby Magazine and a manga adaptation published in the mobile phone magazine Shu 2 Comic Gekkin. Like Mazinger Edition Z: The Impact!, characters and references to other works of Go Nagai appear in this series.

Prior to the events of the anime, the three factions—the Garan Army, the Kiba Army, and the Hachiryoukaku (Aira Army)—battle for total dominance of Machine Island, which they occupy. The island is basically a prison, isolated from the rest of the world. To assure total quarantine, a "Gravity Curtain" was formed within the island: only machines created by the worldwide government WSO are capable of entry to the island. The island also contains vast amount of resources, allowing the three factions to create a near-limitless supply of giant robots for their respective armies.

The WSO has learned that the Gravity Curtain has reached an unstable status and will explode within 66 hours, destroying all of Earth and human life itself. Each of the three factions controls a part of the mechanism responsible for the Gravity Curtain's operation. Knowing the danger of disabling the Gravity Curtain and combating the various factions, the WSO decides to send the Skull Force. The Skull Force is divided into two squadrons – one of which is the 2 member-only Death Caprice Squad, composed of Ken Kaidou and Ryou Magami, pilots of the Mazinger called Mazinkaizer SKL.

The titular mecha of the series, though only called Kaiser by the characters until the end of the series, when Yuuki refers to it by its full name. Unlike the Mazinkaiser featured in the first OVA series, manga, and in video games, this version of Mazinkaiser has a completely different design, sporting a more demonic look. One of the biggest changes is the Kaiser Pilder, the aircraft used to dock onto the crown of Mazinkaiser to control it. It has been renamed as the Skull Pilder and redesigned to resemble more of a human skull hence its name. The Skull Pilder also requires two pilots to control it, unlike the Kaiser Pilder where it is controlled by a single pilot. Another notable change is the eyelids having a blue color as opposed to yellow from past Mazingers. A skull in the center of Mazinkaizer SKL's chest is used in place of the "Z" symbol from the original Mazinkaiser.

The weapons for Mazinkaizer SKL are also different from that of the original Mazinkaiser. This incarnation of Mazinkaizer is equipped with a weapon known as the Ganzantou, a gigantic sword attached to its back. The sword's handle can be extended so it can be used as a pole weapon. The spikes extending at the other side of the Ganzantou's blade is designed to tear apart the innards of its target, as seen in the promotional images.

Another weapon unique to Mazinkaizer SKL are the Breast Triggers. Attached to Mazinkaizer SKL's chest area, they are a pair of handguns SKL can use to shoot its enemies from mid-range. Blades are also attached to the nozzle and beneath the handle of each handgun, allowing the Mazinkaizer SKL to slash at enemies up close. They can also be merged into a battle axe type weapon akin to the Getter Tomahawk and used as a melee weapon. When the Breast Triggers are not in use, they are holstered to the chest, which forms a resemblance of Devilman's face.

When combined with the Wingle's Scrander the Wing Cross, SKL's limiter is released, allowing it to fight at full power, changing its eye color from blue to yellow, as well as unlocking a new set of weapons which are variations of those from past Mazingers. The Tornado Crusher Punch is SKL's version of the Turbo Smasher Punch, with the difference being that Ken Kaido is able to guide them to their target after they are deployed. The Breast Triggers fire laser beams as opposed to solid rounds. The Rust Stream is SKL's version of the Rust Tornado from Mazinkaiser. The Thor Hammer Breaker allows SKL to shoot a huge bolt of lightning towards its target from the Ganzantou, similar to Great Mazinger's Thunder Break. Finally, the Inferno Blaster is SKL's most powerful attack, acting similar to the Fire Blaster from Mazinkaiser.

The female support robot for Mazinkaizer SKL. The Wingle's design incorporates the female mechas used in the Mazinger franchise (Aphrodite A, Venus A & Minerva X) as well as elements of Devil Lady. It is given black and light purple colors with some gold trimmings. The bat-like wings attached to the rear of the Wingle's head act as a Scrander part for SKL (called the Wing Cross), allowing the latter flight capabilities and unlocking its full potential. Like SKL, the Wingle also has a detachable cockpit on its head called the Lady Falcon, which is piloted by Tsubasa in the anime and Scarlet in the manga. Its weapons include a pair of detachable blades that can be mounted on the arms or the legs and used as boomerang-type projectiles, as well as a flail stored in the left breast.