Azetodeth

The main antagonist who is a gigantic three-eyed monster that orders his troops of monsters and kills people. He lives on a bizarre island known as the Demon's King island. 2000 years ago, he destroyed various cities. Mink's dragon great-grandfather Joseph and his minions tried to stop him but the minions got beaten up. Luckily, Joseph had The Gourd of the Saints - an item which took 200 years for him to make and could capture Azetodeth in there. The bad news was he had forgotten to wear his false teeth so he could not recite the spell properly. As a result, Joseph was nearly killed and the gourd got broken, but the pieces had magic power left and they lived as three artifacts needed to reconstruct the gourd. He tries sacrificing his own sons to kill Mink by trapping them all in a room and filling it with lava. Fortunately, they are saved by Rogue, who had anticipated this event and set up a trap door in the floor beforehand in preparation for it. In the end, Azetodeth is killed by a holy sword wielded by Mink, after she had undergone her second ecdysis.
 * Although Azetodeth plays an important role in the manga, he does not in the anime, only mentioned and in a background.