DB Multiverse

Almost 1,000 years later...
The Saiyans often live as outcasts or servants for the Tsufuls. Their strength is surpassed by the weapons of the advanced species. They are worthless.

A particularly intelligent Saiyan then secretly prepares a revolution, and outright foments the genocide of all the Tsufuls.

Universe 1 and 10:
He is then visited by a Kaioshin who stops it dead in its tracks.

Other universes:
On a night of full moon, the slaughter takes place. The Saiyans regain their thirst for blood.

There are no survivors, except for the soul of a Tsuful, Dr. Raichi, who haunts his powerful invention.

Impressed by this violence, they are hired to do the same thing on other planets, by the emperor of their galaxy, the Frost Demon Freeza.