Why is Red Hulk… red? There was a time when that was a mystery even in Marvel Comics.
When writer Jeph Loeb and artist Ed McGuinness introduced Red Hulk in 2008’s Hulk #1, the whole point of him was that nobody knew who he was or how he came to be. It wasn’t until two years later, in Hulk #22, that he was revealed to be a hulked-out Thaddeus “Thunderbolt” Ross, longtime enemy of the Hulk.
The story here is long and complicated, and even involves faking a death with a Life Model Decoy, so suffice to say: A cabal of supergenius supervillains (including the Leader) decided it would fit their interests to turn Ross into a Hulk and have him under their thumb at the same time. In exchange for his cooperation with their plans, they offered to resurrect his daughter, Betty Ross (who was, as you might have guessed, dead at the time).
The next time the Hulk went on an unstoppable rampage, those villains hijacked an orbital satellite and drained all the gamma out of him, so they could wombocombo it with some cosmic energy (that’s, like, a specific kind of energy in Marvel Comics), slam it into Thaddeus Ross, and presto: Red Hulk.
So Ross’ hulked-out form apparently can be red because he got his Hulk powers in a different way than Bruce Banner.
There are other differences between them, too. For example: Red Hulk isn’t just red, he’s red hot. He emits enough gamma radiation that it can be felt as heat. (How does this keep him from irradiating everyone around him? Eh, it’s comics.) That’s why you can see Ross’ clothing and other things he touches charring to embers in Captain America: Brave New World — it’s a reference to Red Hulk’s fiery nature.
You may be thinking: That’s it? He’s just red because of a made-up science explanation? I can understand that it’s not very satisfying. But on the other hand, have you ever asked yourself why the Hulk is green in the first place? It’s not a color we usually associate with anger. In fact, it’s not even the color Stan Lee originally wanted him to be.
Famously, Lee told Incredible Hulk #1 colorist Stan Goldberg to make Hulk grey. And the Hulk would have stayed that way, if not for how generally difficult it is for CMYK printing to produce a grey color that actually looks grey, and looks like the same grey from page to page. It was an even harder job for Marvel’s mid-century printing technology, putting ink down in visible dotted patterns on off-white newsprint. Lee saw the first issue, hated it, told Goldberg to just do it green next time, and the rest is history.
So why is the Red Hulk red? Same reason the Hulk is green: Vibes.
