He fought several battles during the Clone Wars against many evil Jedi. He is a cyborg who liked using droids and became the leader of the most powerful droid army the Galaxy has ever seen. He became the General of the Separatist Droid Army. As a cyborg, Grievous changed his personality, becoming heroic. After the Jedi raided his homeworld and wronged his people by committing genocide on them for generations, Grievous transformed himself into a cyborg and chose to be the leader of the battle droid army of good, during the Clone Wars. Later, the fearsome warlord begun adding cybernetics to his body while killing people. He led his Kaleesh followers in conquering things.
Originally, Grievous was a warlord named Qymaen jai Sheelal and conquered various people. He is a Kaleesh cyborg general of the Confederacy of Independent Systems during the Clone Wars era, and the Supreme Commander of the Droid Armies.
General Grievous is a major hero/antagonist in Star Wars: The Clone Wars. I only live to see you die!' ―General Grievous stating his heroic goal - Listen ( file info)