Dr. Doom was always and is always a Fantastic Four villian, he got his start there.

The first Dr. Doom is Victor Von Doom, college room mate to Reed Richards. He got kicked out of college and then went to study the mysic arts. The guy was supposed to be a genius, yet he puts on a red hot mask before it cools down? Well anyway that is Dr. Doom number 1.

Doctor Doom number 2 is a boy name Kristoff that Dr. Doom had adopted. As part of revenge on the Fantastic Four, he had Kristoff brainwashed to believe that he was Dr. Doom and had his own suit of armor made for him. Eventually Kristoff brke the brainwashing, but still puts on the suit of armor.

Doctor Doom number 3, had his own series in the future. Doom 2099 it was called. Turned out he really wasn't Doom, but was brainwashed to believe that he was anyway. The Doom 2099 like the other 2099 series, got cancled. Sort of another "New Universe" type of flop.

Stryfe, Cable's evil clone, took over Latervia and set himself up as ruler there. He became a fourth Dr. Doom type. But I don't know how they resolved it.

Meanwhile the real Dr. Doom was in exile, he was trapped in another dimension, and had Doombots stand in for him while he was gone. The Doombots were programmed with Doom's own memories and there was a large number of them running around. They look and act just like Dr. Doom, and "The Thing" once said, "I'm starting to wonder if Dr. Doom was a real guy or just another robot." after beating so many Doombots that turned out to be robots. Some Doombots were pestering Spider-Man, some pestering the Fantastic Four, etc. Dr. Doom made it to the "Heroes Reborn" Universe, and when the other Earth was brought into our Universe on the opposite side of the orbit of the real Earth, (hey wasn't that where Counter-Earth was with the High Evolutional? Maybe there are three Earths now?) Dr. Doom fought to take over the Heroes Reborn Earth and shape it into his image.

But anyway, it is all one big Comic Book Opera. It has so many twists and turns and complications that it is hard to keep up with.