I was never a fan of Dr. Doom, but I had a few ideas after drawing this. Basically he went up with the team and was the only one who was completely unaffected by the accident that gave the others their abilities. His envy of the Four drove him to seek out ways to gain power. He sees Dr. Fantastic (How is that not already his name!?) as a rival pioneer in the field of exploratory hyper-science.
The mask was once part of the armor worn by his ancestor, the legendary founder of Latveria.