OVAs that come with the limited premium edition of volumes 16 and 20 of the manga series.

After conquering the galaxy, mankind has reached its apex and is now on a steady decline. The resources of the universe are diminishing, and around 500 billion humans begin to return home to Earth. Thus begins a war between the various factions of humans for control of the planet. Eventually, an authoritarian government known as the Gaia Sanction prevents the re-population of Earth. Captain Herlock was one of the Elite Wing who was tasked by the Gaia Sanction to defend the Earth. His fleet of ships was unstoppable under his command. However, the Gaia Sanction allows a diplomatic elite to immigrate to Earth, which angers Herlock. He goes rogue and fires upon the diplomats and the rest of his fleet. He decides to unleash dark matter on the planet to make it uninhabitable, but also becomes engulfed in it which immortalizes him. One hundred years have passed, and the legendary Captain Herlock is still at large, with only the Arcadia under his control. The Gaia Sanction continues with their plans for control over the Earth, while hiding its true state. But Captain Herlock is preparing for one final showdown with them, which will determine the fate of the world!

Three hundred years ago, in the frigid land of Siberia, Jubei Yagyu engaged in a fierce battle with Kitaretsusai of the Northern Yagyu clan. The duel was costly, as his daughter Freesia was frozen in suspended animation. As a result of global warming in the present day, Freesia breaks free from her icy grave and moves to Japan as a middle school transfer student, where she befriends Jiyuu Nanohana. Little does Jiyuu know that Freesia is targeting her to acquire the coveted Lovely Eye Patch, which Freesia believes is rightfully hers.

In the year 3990, the immortal Oldna Poseidal rules Pentagona, a war-torn solar system of five planets. Daba Myroad is a survivor of the Yaman Clan, just one of numerous native societies nearly wiped out by the tyrant. Living on the remote planet Koam with his friend Mirao Kyao, Daba possesses L-Gaim, a humanoid mecha known commonly as a "Heavy Metal" and the last known relic of the Yaman Clan. The pair befriend Fanneria Amu, an aspiring actress, and Lilith Fau, the last surviving fairy in Pentagona while on the run from a band of thieves attempting to steal L-Gaim. Daba promises to fulfill the dying wish of one of the thieves hunting him—an honorable act that leads him to the powerful merchant Amandara Kamandara. With their mission in sight, the ragtag group will face powerful adversaries and become entangled in a rebellion against Poseidal's reign.