I think to fully grasp Reed and Victor’s connection, you have to view it from both sides, because I think a great deal of what Victor feels that’s positive for Reed comes out of Reed’s positive feelings for him. After all, it’s Victor who says “Nobody sees me. (Only Reed did.)”
(Invincible Iron Man #597)
To get to Victor, I think you have to start with Reed, and what you have to understand about Reed is that Reed, despite being in most other ways pragmatic and in what’s so rarely discussed about him, utterly believes in the power of love, beyond all else, beyond himself.
“Because what man is a man that doesn’t risk everything for the people he loves? I am flawed that way.” – FF #21
“You see surprised that I would be willing to sacrifice myself for my family. Why?” - New Avengers v3 #3
So you can’t start from the idea that Victor met Reed in college and fell in love with him quickly, because Victor isn’t that person. Victor, especially in his youth, is hardened by the world, angry and vindictive, and utterly prepared to lash out. He already has his armor on, so to speak. After all, when Reed tries to help with his experiment, it’s an honest gesture – but the idea of anyone being superior to him in any field, especially in his own domain, is so abhorrent to Victor that he lashes out, and that’s how the accident happens. And of course he blames Reed for it – logically, Reed is the only person besides himself he can blame, and Doom cannot blame himself, at least, not on any surface level. But Doom harbors a great deal of hatred – so what makes Reed special? What makes him continually worthy of tormenting, of torturing, the focal point of Doom’s obsession? Doom accuses Reed of being soft and sentimental – but is it that softness and sentimentality that Doom focuses on not because he honestly wishes to stamp it out, but because he craves those emotions focused on him?
“He was a genius.” - Infamous Iron Man #7, in Doom’s hero phase, in what I think is one of his most honest and vulnerable moments, where he admits he misses Reed and Sue. I think it’s not fair to discuss Reed and Doom without discussing them as two halves of a coin – Claremont established this brilliantly in both his Fantastic Four run, which at one point sees Reed trapped in Doom’s armor, and in his earlier Fantastic Four vs X-Men, and Waid, who I otherwise think doesn’t write the best Doom in the world, strengthened that when he had Reed use Doom’s machine to reach the afterlife to save Ben. So you have this huge similarity: they both view themselves as being capable of or willing to defy everything to save the people they love the most. Reed in his worst moments behaves like Doom: arrogant, selfish, secretive, lonesome. He invades Latveria; in Doom’s armor, he becomes almost possessed, behaving more and more like Doom. This is isn’t to say, though, that they have more similarities than differences. Doom is monumentally proud. Reed, despite everything, is ultimately humble. Doom is power. Reed is knowledge. And Reed is balanced out by other factors – Sue, Ben and Johnny, his children, his work, the Fantastic Four. Doom leaves himself off-kilter by choice, because he cannot be open enough to accept help honestly, to establish a connection that might make him whole. Reed is content; Doom is longing. Reed believes that, given the circumstances, given the choice, given the opportunity, Doom can change. To be Doom, Victor has to believe that Doom is a constant. It’s a constant tug of war between Reed and Victor’s beliefs.
On some level Doom knows that Reed completes him, that together they make a perfect whole, which is why he both hates him – and, in fantasies, models himself after him. There are a couple of alternate Doom/Sue realities born out of Victor’s fantasies – the one in Millar’s run, and the one in Secret Wars (2015), but I think to view this as about Victor’s desire for Sue at all is a mistake. He makes himself in Reed, he usurps Reed’s position, questing for the love that Reed offers but that Victor cannot accept from him. So instead, he makes it a conquest. Take Reed’s place. Take Reed’s wife. Take Reed’s children. (He already views himself as Valeria’s godfather and if there’s anyone he’s especially soft on, it’s her, not to mention that, unbeknownst to them both, Doom’s adopted son Kristoff is Reed’s biological half-brother.) It’s not about loving Sue. It’s about becoming Reed, and in that act of conquest being able to accept that love. Except that’s not how love works, so ultimately the act is hollow, and Victor is still unsatisfied. He wants Reed’s love; he cannot accept it. But this is still a man who died for Reed’s cause and Reed’s family, and who is inextricably connected with them.
There’s a potential future oneshot I really like called Fantastic Four 100th Anniversary Special, which was part of a line that envisioned where series would be on their 100th anniversary, which sees Doom as part of the Fantastic Four family:
And I think it’s the best path possible for him, if he was actually able to embrace that connection and lean into the family and find the acceptance and love he’s clearly been craving. Because after everything, Reed is ultimately willing to forgive Doom, because they have such a connection and understand each other in ways few other people can. It’s just that Reed is, most of the time, the only one who can admit that.
(Fantastic Four #562 – it was a Sue from a far flung future who used Doom, Johnny, and Galactus as a power battery that Doom killed, for context. If you want to talk character similarities, Sue and Doom are both far more ruthless than Reed.)
In conclusion, Reed, to Victor, constantly: