Douglas Birely was a genetic researcher. He experimented with radioactive causes of mutation at a private research company in California.

He asked his employers for clearance to experiment on a live subject with radiation to see if, like so many people he had heard of in the news, the subject would develop super-powers from radiation exposure. His employers refused and he illegally tested a radiation burst on himself. It did not give him super-powers; instead he contracted lethal skin cancer.

Because of his cancer he was forced to don a protective suit of armour to keep himself alive. Birely was fired.

Birely learned of a highly radioactive meteor. It had fallen to earth near the Aleutian Islands.

Using the last of his savings, Birely got to the islands, stole the meteorite and set up a laboratory. He discovered that the meteorite, which he called the lifestone, had the power to strongly mutate living organisms into super forms. He used it to create giant monsters, including a mutant bat he called Batragon.

Dr. Demonicus was among the 43 to escape the Raft. He was recruited into the Hood's organized group of supervillains and was later defeated by Doctor Strange in a battle with the Secret Avengers.