Tharok

Tharok is the leader of the Fatal Five.

Tharok is a small-time crook, who tries to impress his bosses by stealing a small nuclear device. It detonates unexpectedly when the local police fire on him, vaporizing one-half of his body. The people of his world, holding life sacred, rebuild him using robotic parts. This boosts his intelligence dramatically, but leaves his evil tendencies unchecked. In his early appearances, he wore clothing that only covered the organic half of his body. Tharok's cyborg brain also allows him to control Validus, the mindless monster member of the Fatal Five.

One of the Fatal Five's main attempts to defeat the Legion is masterminded by the Dark Man, the being who organized several teenage refugees from the planet Dryad into the League of Super-Assassins. During this time period, it is revealed that the Dark Man is actually a clone of Tharok, grown from tissue removed from Tharok's body during his cyborg reconstruction. When the scheme to destroy the Legion fails, both Tharok and the Dark Man are seemingly destroyed and the Fatal Five eventually disband