The Konatsian warrior Tapion explains to Bulma that a race known as the Kashvar, power hungry aliens who believed themselves to be the superior beings in the universe, re-awakened an evil monster called Hirudegarn in an attempt to easily eliminate the population of Konats. Centuries ago, ancient warrior Konatsians defeated the monster, but the Kashvar had found a way to resurrect the beast using dark magics. Over the course of the following year, Hirudegarn wiped out nearly half of the planet's population.
The enchanted items
It was not until a Konatsian Wizard came upon an ancient enchanted sword and two magical ocarinas that there was any hope for victory. These ocarinas were given to Tapion and his younger brother Minotia in hopes of using their melodies to distract Hirudegarn. The enchanted melodies worked, and consumed the monster with a great amount of rage. While distracted, the wizard drew the blade and cleaved Hirudegarn in two.
The wizard then sealed each half of the beast inside of Tapion and Minotia. The brothers became heroes, but the Konatsian war council ordered them to be sealed inside specially designed enchanted music boxes and sent into the far reaches of space until all of the Kashvar could be brought to justice. Unfortunately, the Kashvar are never all captured, and the brothers float through space for a thousand years.
1000 years later
Main article: Dragon Ball Z: Wrath of the Dragon
Eventually, the last surviving member of the Kashvar, Hoi, found both of the music boxes. He managed to somehow open Minotia's box, and the lower half of the monster was released. Hirudegarn proceeded to kill Minotia, and Hoi took control. Hoi, then, proceeded to travel to Earth, in hopes of using the Dragon Balls to open Tapion's music box and free the top half of Hirudegarn. After tricking the Z Fighters, he successfully released Tapion. Later on, the Z Fighters battle Hirudegarn, who was fully released from Tapion's body and had merged with the lower half.
The monster eventually transforms into a new, more powerful form, where he is eventually killed by Super Saiyan 3 Goku's Dragon Fist attack. Tapion gives his sword to Trunks and uses Bulma's Time Machine to travel back to his own time.