Bragen

Bragen was the head of security for the human colony on Vulcan and the leader of the rebel group fighting against the governor, Hensell.

He shot and killed the Examiner that had been originally summoned to Vulcan, then framed Quinn for rebel activity, hoping to be made the deputy governor himself to put himself in a position of genuine power to overthrow Hensell.

He planned to use the Daleks to aid him in seizing control of the colony, unaware that the Daleks were secretly planning to conquer it themselves.

Once he had a Dalek exterminate Hensell, Bragen assumed command of the colony and decided to have the other rebels killed to secure his power.

When the Daleks turned on the rebels, Bragen tried desperately to regain control but failed.

After the Daleks were destroyed by the Second Doctor, he was on the verge of shooting Quinn when Valmar entered and fatally shot Bragen. (TV: The Power of the Daleks)

Bragen