Warrien

Warrien was a representative of his home galaxy in the Galactic Council which allied with the Daleks in their plan to conquer the Solar System. Warrien wore a protective pressure suit and appeared to have a human face beneath his cowled helmet. He disappeared from later meetings, his place taken by Celation.(DW: Mission to the Unknown)

Behind the Scenes
The actor who played Warrien did not receive a credit, but Johnny Clayton and Len Russell played 'Alien Delegates'. It remains unclear, to date, which of them played Warrien.