Gyaasuka Daimao, also known as the Ogre-King Gyaska, rules Wonder Island as the story's primary antagonist. This evil entity possesses a tear that is a vital component for a love potion. The recipe, found on a videotape left by Senbei Norimaki's deceased father, requires combining this tear with Senbei's own bodily substance to create a concoction capable of making anyone who drinks it fall in love with him.

To obtain the tear, Senbei Norimaki journeys to Wonder Island with Arale Norimaki and Gatchan, traveling in the Super Mecha "Ping-Pong." During their quest, they encounter a vampire woman whom Senbei aids by providing Type A Emergency Insta-Blood. In return, she directs them to Gyaasuka Daimao's location, enabling their mission to proceed.

Gyaasuka Daimao exists solely within this adventure, serving as a formidable obstacle whose emotional response—specifically his tear—drives the central quest.