The most popular Hulk is without question Bruce Banner's original version, with She-Hulk checking in not far behind him. But Marvels fans know the Red Hulk beats both of them when it comes to the coolest powers and abilities.
The Red Hulk first appeared in the pages of Hulk (2008) by Jeph Loeb and Ed McGuiness. The real identity of the red giant was Thunderbolt Ross, the Air Force general who hunted the Hulk for years and was actually in charge of the project that turned Bruce Banner into a monster. Ross would take part in a Super Soldier program from Doc Samson, A.I.M., and the evil Intelligencia, and would transform into the Red Hulk - all in an effort to take down Banner... and a promise he would see his daughter Betty again. The program produced a new Hulk -- and one with even more 'incredible' abilities.
Red Hulk's power set is more than impressive. He remains intelligent and aware, but isn't afraid to be brutal. Like the Hulk, he has incredible strength and durability, gets even more powerful the angrier he becomes, has a healing factor, and is invulnerable to most attacks. But, Red Hulk also has the ability to absorb energy types, including gamma radiation - a skill he put on display in The Incredible Hulk #600, draining a rage-filled Hulk's gamma radiation and turning him back into Bruce Banner. The angrier he got, the more heat he emitted, leading to his body temperature rising. The Red Hulk also could shoot burn fire from his eyes, as Spider-Man sadly found out.
While Red Hulk had Bruce Banner in his sights, he served more as an anti-hero opposed to a straight-up hero or villain. He fought heroes, but he also fought villains. In his time as the Red Hulk, Ross has fought alongside the Avengers and led his own version of the Thunderbolts alongside Elektra, Punisher, and Venom. He even fought against the Hulk but was ultimately outsmarted as his foe figured out as long as he didn't get angrier, Red Hulk couldn't take his gamma radiation - leading to Ross to overheating.
Ross would be depowered as Red Hulk, after Doc Green (the smart Hulk) captured him and injected him with a cure. That wouldn't be the last version of Red Hulk, as General Robert Maverick would assume the role after receiving a Bannerman Gene-Enhancement Package (Hulk plug-in) from SHIELD. Maverick would fight alongside the U.S. Avengers and eventually have the Hulk Plug-in burned into him - giving him red skin - but the Hulk would later absorb the remaining gamma radiation and turn him back into a human. The Red Hulk has not returned since, and Ross would later be killed. While his tenure as a new Hulk didn't last very long, Red Hulk proved to be a powerful new character who breathed new life into the character. Will he ever return? It's possible. It would be great to see since the Red Hulk is one of the coolest, most unique versions of the Hulk ever.