Branded at birth as the first legendary super saiyan in roughly 1,000 years, Broly is defeated by the protagonist Goku in the prequel to "Dragon Ball Z: Bio-Broly." Broly's frozen blood is used to create a clone by Jaguar, which, upon awakening, is drenched in a bio-liquid designed to create super bio-fighters. The mutant-clone of Broly, Bio-Broly is the main antagonist of the feature film.
Goten is the second son of Goku and Chi-Chi and the younger brother of Gohan. He is half-saiyan and half-human. As a child he excelled in martial arts and possessed a power level higher than Gohan had at that age. Goten discovers Bio-Broly in "Dragon Ball Z: Bio-Broly" and with the help of his best friends Trunks and Krillin, defeat Bio-Broly with a triple Kamehameha blast into the sea.
Trunks is the human/saiyan hybrid son of Vegeta and Bulma. At times he is referred to as Kid Trunks to distinguish him from his older time-traveling future-self, Future Trunks. He has light purple hair and has the ability to transform into a super saiyan. In "Dragon Ball Z: Bio-Broly" Trunks accompanies Goten and Krillin to discover Jaguar building super bio-fighters, among which is Broly's clone.
The main protagonist of the "Dragonball" franchise, Goku is one of the most powerful saiyans and the first to reach super saiyan levels. In "Dragonball Z: Bio-Broly" Guko makes a brief appearance at the end of the film. He is informed that Broly is causing trouble in Hell and so journeys with Pikkon from the Other World to confront him.