The Jaku(Evil) Empire

Gojigenjin

Belzeb The Gojigenjin in charge of taking Earth for the Jaku Empire. With Falzeb's help, he empowers the Jaku Beasts to gigantic proportions, as well as piloting both Jaku Satan and its upgrade, and the Super Jaku Beast produced by combining Jaku Satan with a powered-up Jaku Beast. He is instrumental in defeating Warusar after being rejected by him, but still fights Raijin-Oh in the end because his warrior code demands it. Later he is trapped by Gokudo due to his failure and betrayal, but freed by Falzeb and the Raijin Medals, after which he helps Raijin Oh and the Earth Defense Class defeat Gokudo.

Falzeb This fairy is linked in some manner to Belzeb. She lives inside Belzeb's chest, and focuses his power to power up the Jaku Beasts and summon forth the Jaku Satan. She is able to survive without him, but does care for him.

Taida Belzeb's subordinate. He is responsible for the care and handling of the Akudamas, the bioweapons(in a sense) of the Jaku Empire. Over time he becoems sympathetic to the cause of Earth and eventually immigrates.

Gokudo The villian of the first and third OVAs. Having heard about Warusar's defeat, he goes to see this planet for himself. At some point between the final episode and the first OVA, he imprisoned Belzeb on his back. He also has Falzeb with him, whose goal is to free Belzeb, and is working for Gokudo in that hope. He has a crystal sword motif rather than a pure crystal, and his robot, Jaku Lucifer(on the left) is formed from a glass sword. In OVA 3 he eventually combines Jaku Lucifer with the original Jaku beasts from the series to transform it into Great Jaku Lucifer(on the right) to defeat the Earth Defense Class.

The Emporer

Warusar The emporer of the Jaku Empire. He sent Belzeb to take Earth in their name, and granted him increases in power twice to help him accomplish his mission. Finally, after he had enough with Belzeb's failures, he struck out at Belzeb and attacked himself, setting the stage for his own downfall.