Thawn

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

Biography
Thawn secretly conspired with Rohm-Dutt to have the native Swampies wiped out. He set Rohm-Dutt up to deliver them weapons; this would allow him to justify their extermination as they would be a threat.

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