Thawn

Thawn was the controller of the methane refinery on Delta III.

Biography
Thawn conspired with Rohm-Dutt to have the native Swampies wiped out. He set up Rohm-Dutt to deliver them weapons; this would allow him to call them a threat, justifying their extermination.

When Kroll appeared, he tried to kill it with a orbital strike. The Fourth Doctor cut the power, halting the countdown. The Swampies attacked the refinery and killed Thawn with a spear. (DW: The Power of Kroll)