Critas

Critas was an Eternal who took part in the race for Enlightenment.

Biography
Critas and his crew all dressed in the fashion of Ancient Greece. His ship was a trireme, designed to the same period.

However, the Fifth Doctor noticed via the video screen aboard Striker's ship, the Shadow, that Critas was wearing an anachronistic 17th century Spanish signet ring with a large red crystal.

During the race, Critas was rounding Venus and was about to overtake the Buccaneer when Captain Wrack of that ship destroyed his through the power of the Black Guardian. Critas and the Eternal officers aboard his ship were returned to their realm, though the human crew of the ship all perished. (TV: Enlightenment)