If not, why wouldn't he?
Given that a large part of Doom's motivation is to be recognized as being better than Reed (really, that's probably more important than world conquest to him), one would think that Doom not only had a portal but traveled the negative zone extensively. Maybe even allying himself with Annihilus.
Anyway, just a stray thought.
Replies
That would be an interesting premise, but Dr. Doom is not better than Reed Richards, he only thinks he is. Me, I always tied Mr. Fantastic's discovery of the Negative Zone to the "negative zone" that had previously entrapped the Inhumans in Attillan. It was his study of that barrier which (somehow) led to his discovery of the other dimensional Negative Zone. I also liked the way Captain Marvel's nega-bands were also tied to the Zone. Fabian Nicieza had a whole (comic book) "scientific" explanation behind how they worked, then another writer came in an arbitrarily linked them to the Microverse.
Sure, but I think that Doom would look into anything that he knew Reed was looking into, just to make sure that Reed didn't gain some advantage over him. Also, even if we postulate that Doom isn't as smart as Reed, he's no dummy, either, so I don't think it would be beyond him. How big is the Negative Zone meant to be, anyhow? Doom could've been committing all sorts of shenanigans in there that we just haven't heard about. There could be a whole planet Victoror in there where Doom is regarded as a hero, for all we know.
Jeff of Earth-J said:
What do you want from me? I said it was an interesting premise, didn't I?
"How big is the Negative Zone meant to be, anyhow?"
It is my understanding that it is infinite.
"There could be a whole planet Victoror in there where Doom is regarded as a hero, for all we know."
Come to think of it, wasn't that the premise for the post-Heroes Reborn Doom?
Sure, a lot of Doom's motivation is to be perceived as better than Reed Richards, but he doesn't want to be perceived as copying him. Plus, he does have his own fish to fry. Exploring the Negative Zone might just be lower on his to-do list.
That's what minions are for! Send in the minions to explore, and if they don't come back ... well, there are always more minions.