Kzer-Za was a Green Ur-Quan, a scientist, during the time of the Dnyarri slave empire. It was he who found how to defeat the Dnyarri in discovering that the creatures would disconnect from a dying or seriously injured slave.
During the brief moments of lucidity that the Dnyarri gave their minions in the later part of their rule (probably out of laziness and complacency) Kzer-Za devised a plan. He waited until he was near a communication console and injected himself with a lethal dose of acidic poison. Before dying in agony he gained control of the device and broadcast his findings to every Ur-Quan on the planet.
That day the Slave Revolt against the Dnyarri began as Ur-Quan everywhere began hacking off their own limbs, stabbing themselves with broken glass and worse things. For every pain they inflicted on themselves, they were able to kill another Dnyarri, and the death of each Dnyarri would free more Ur-Quan. The blood bath continued until every Ur-Quan and every member of the former Sentient Milieu in the galaxy was free.
The name of Kzer-Za is legend among both Ur-Quan subspecies as a Martyred Genius. The Green Ur-Quan named themselves in his honor. His research also led to the invention of the Excruciator by the Kohr-Ah, a violent device that is implanted directly into the brain and causes constant, horrifying pain.