Dr. Terror is the mad scientist in charge of the Blackguard’s Artifact Weaponization Project. Most of the time he is occupied conducting evil experiments, but now and then he invades the archipelago to terrorize innocent islanders. Nobody really knows where and when Dr. Terror will make his first appearance, but rumour has it that if you successfully defeat Lt. Hammerman’s Headquarters, the Blackguard will send Dr. Terror after you.
Dr. Terror’s bases are the only place you can find Dark Power Stones, and on top of that he stockpiles lots of gold and building resources. However, defeating him does not give you Victory Points. Also note that Dr. Terror is incredibly persistent! Destroying his base just once will only make him come back stronger and angrier, so you need to keep sending in waves of attacks to exhaust Dr. Terror’s power.