Bemar

Bemar was the ruler of a human colony planet Publius and served the Druden.

Ruler of Publius
Whilst on the way to Publius during the time of the Second Galactic Empire, Bemar became the next ruler by mysteriously deposing the planned leaders one by one. (DWAN: Plague World)

Plague
Bemar served the insectoid race the Druden when they invaded the planet. When the Druden infected the planet with the plague, Bemar was given an antidote to survive the disease. She was to keep people calm as they disappeared and were fed to the Druden younglings.

When the Doctor, Adric and K9 arrived on the planet and entered the assembly, Bemar accused them of being the cause of all the trouble. The Doctor quickly deactivated K9 so he couldn't be used and escaped, thanks to Kidson, who opposed Bemar. Adric was chained up. (DWAN: Plague World)

Death
The Doctor and Kidson stopped the Druden. Kidson sacrificed himself to destroy them, before Bemar could teleport the Druden to the village the Doctor activated K9 through a signal which once activated K9 used his photon beams on her destroying the transmitter and presumably killing her. (DWAN: Plague World)