Beaus

The Master of Beaus or simply Beaus was a Galactic Council member.

He had apparently been persuaded to join the alliance by Zephon. By remaining low-key at the meetings, he survived until the final meeting, where he strongly challenged Mavic Chen, and was then imprisoned by the Daleks. With Celation, Mavic Chen and Malpha, the remaining members of the Council, he agreed to go back to his own people and warn them about the Daleks' invasion plans and to fight against them, upon their escape from Kembel. (TV: Mission to the Unknown, The Daleks' Master Plan)

Beaus was shot and killed by Mavic Chen. (PROSE: The Mutation of Time) By another account, Chen instead killed Gearon, and Beaus survived (TV: The Daleks' Master Plan) to join the Syndicate to seek revenge on the Doctor for the events on Kembel. By this account, he was ultimately killed by Anya Kingdom. (AUDIO: The Perfect Prisoners)

Appearance
Beaus was a tall alien with his face indistinguishable due to the dark visor and chlorine fumes he breathed, wore a protective suit. His helmet had an antenna on top. (TV: Mission to the Unknown, The Daleks' Master Plan)

Behind the scenes

 * The actor who played Beaus in Mission to the Unknown did not receive a credit, but Sam Mansary played an "Alien Delegate", and is of African descent, which matches the still shots from the episode which appear to show a dark-skinned actor inside Beaus's space suit.
 * Prior to the recovery of episode two of The Daleks' Master Plan, Beaus and Sentreal were often misidentified with each other, including in the novelisation.
 * Gerry Videl played Beaus in The Daleks' Master Plan. (DWM 272)