Brain Machine

The Brain Machine was a sophisticated computer used by the Daleks.

When Zeg challenged the rule of the Dalek Emperor, the Brain Machine decided that the two would duel to lead the Daleks. (TV21: Duel of the Daleks)

Later, when a radioactive cloud of metal-eating rust threatened to destroy the Daleks, the Brain Machine was consulted by the Black Dalek on how to destroy the cloud, which inadvertently created the rust plague. (TV21: Plague of Death)