Commander Sharrel was the leader of a group of Movellans who landed on Skaro to find and destroy Davros during their war with the Daleks.
When the Fourth Doctor became involved, Sharrel attempted to kidnap the Doctor and use him to reprogram the Movellan battle computers so that they could win the war. The Doctor escaped him.
In an attempt to destroy Skaro, Sharrel tried to activate the Nova device, which would have destroyed the planet, but he was stopped by Romana. (DW: Destiny of the Daleks)