Darrius

Darrius was an elderly scientist who experimented on the plants in a jungle on Marinus, increasing their growth rate and making them more aggressive. He kept one of the keys to the Conscience of Marinus and made a fake key to fool anyone who tried to take it.

Before dying, Darrius told Ian Chesterton where he had hidden the real key, "D-E-3-O-2", though both Ian and Barbara Wright was confused as to what this meant. (TV: The Keys of Marinus)


 * Darrius was never referred to by name on-screen, only in the credits. He is also unnamed in Philip Hinchcliffe's novelisation of the story, being referred to instead as simply 'the old man'.