Master Moo

Mysterious Master Moo is the main antagonist of the anime, Monster Rancher. He never appeared in any game. Moo is pure evil.

He was a gigantic dragonlike monster that scientists created for war, but he was too evil and powerful to be stopped. So the scientists created the Phoenix, the only monster whose power rivaled Moo's. The scientists made a device to turn all monsters into Mystery Disks.

Eventually, Holly's father found the Mystery Disk containing Moo, and Moo was merged together with him. Moo assumed a humanoid form, resembling General Durahan, except with hold armor, a red and black cape, long white hair, a pure black face with red eyes, a helmet, and two goat horns.

Moo gathered several followers, each bearing a crest called the Baddie Crest. The Baddies were the evil monsters that served Moo. The strongest of Moo's servants were the Big Bad Four: Pixie, Gali, Gray Wolf, and Naga. Moo seeked out the Magic Stone, which was in the possession of Holly, and wanted to use it to find and regain his original body.

The Searchers (the protagonists, consisting of Genki, Holly, Mocchi, Suezo, Golem, Tiger, and Hare) fought Pixie, and she eventually switched sides. Afterwards, Moo found and kidnapped Holly to take the Magic Stone. Although the others rescued her with the help of Vulcan and the Pirate Dragons, Moo found the way to his original body and arrived at the area.

While the Baddies dug through the ice for Moo's original body, the Searchers fought Gali and Gray Wolf. Gali was killed by Mocchi using his Mocchi Cannon attack, and Gray Wolf was killed in 1 on 1 combat with his brother Tiger, who sent his horn through his Baddie crest. Right after Gray Wolf's defeat, Moo found his original body. His Baddies dug the dragonlike body gree of the ice, while Naga attempted to kill the Searchers.

By the time Moo merged with his original body, the Searchers had already fought Naga, resulting in Naga getting hit with a Mocchi Cannon, hanging onto the edge of his castle on the cliff, and let go and fell to his death. Moo attempted to invade a village, but was weak against sunlight. When the sun rose, he was seriously weakened, and retreated back to his hideout.

For most of the following episodes, Moo remained severely injured inside his hideout, and sent Evil General Durahan after the Searchers. Durahan's many servants were defeated, but he wanted the Magic Stone for himself. Once he got the stone, he betrayed Moo and nearly killed him, but by this time Moo was almost back at full strength. However, his assistant Lilim betrayed him for Moo. The Searchers and Durahan and Lilim fought on Durahan's ship, and in the end, a Weed got the stone and took it to Moo. Durahan's troops, who now served Moo instead of Durahan, shot down Durahan's ship. Durahan killed Lilim before dying himself when the ship crashed.

Moo got the Magic Stone and became immune to the sun. He attacked the Searchers just as they found the frozen Phoenix, and mortally wounded Pixie. However, she was healed when Big Blue fused with her to form Granity, sacrificing his existence in the process. Monol informed the Searchers that the Phoenix was really Mocchi, Suezo, Golem, Tiger, and Hare, and so Genki fused them together just as Moo was going berserk and destroying everything, even his own castle and the Baddies.

The Phoenix fought Moo and grabbed onto him. Moo realized that he and the Phoenix were destined for eternal combat, and that he couldn't let the Phoenix nor himself exist. At this, the Phoenix and Moo destroyed each other, vanishing in an explosion of light.

In Season 3, the role of antagonist shifts to General Durahan, who is resurrected as a head by a Weed (who in turn becomes a cyborg), and attempts to absorb Moo's soul, which was trapped inside a disk after his death. In the final episode of Season 3, Durahan and his servants, Gobi, Mum Mew, Poison, and Weed, are fused with Moo's soul to form a gigantic warrior, who sucks the Phoenix and the others inside them, but when Durahan and the others give the Phoenix their energy, he is able to attack Moo's soul within, destroying it. The evil is last seen rising into the air and exploding.