While the MCU showed Thanos besting the Hulk hand-to-hand, the original comics are a different matter. Which of the two is really the strongest?
Fans of Avengers: Infinity War will remember the film starting with the Mad Titan, Thanos, quickly defeating the Hulk in hand to hand combat. This is a feat which had so far seemed impossible in the MCU, firmly establishing Thanos as a physical force to be reckoned with. But while Thanos is powerful in the movies, his Marvel Comics counterpart takes it to the next level.
In the comics, Thanos' strength has allowed him to trade blows with some of the most powerful cosmic entities in the Marvel Universe, and beat them with just his pure physical might. But that doesn't mean his victory is assured, and one of his most able challengers is his MCU opponent. So exactly how strong is Thanos, and does he actually have the raw strength needed to defeat the Hulk?
Thanos is an Eternal, born on Saturn's moon of Titan. He is also a mutant, being subject to the Deviant Syndrome, which explains his purple appearance while the other Eternals look more like normal humans. His Eternal physiology is one of the features that grants him his strength, but he has gone on the augment it with bionic enhancements and mystical enchantments that make him even more powerful. His strength levels were even more significantly boosted due to Death augmenting his abilities once the two became allies.
Like the Hulk, Thanos can also gain physical power by drawing from a source of energy, and whereas the Hulk's strength is based off gamma radiation, Thanos is able to increase his physical might by channeling cosmic energy into himself. All of these factors lead to Thanos being easily able to lift 100 tons, putting him in the same category as Thor, Hulk, and powerful celestial beings. Thanos is also skilled with hand-to-hand combat and was trained in the Art of War while on Titan.
The Mad Titan has had plenty of opportunities to demonstrate his strength level. In his first appearance in Iron Man #55, Thanos and Drax the Destroyer destroyed a large chunk of a planet during their battle, a battle in which Thanos was the victor. In Thanos: The Infinity Revelation #1, he was able to dispatch both Beta Ray Bill and Ronan the Accuser, even snapping Ronan's Universal Weapon in half with his bare hands. Thanos was able to battle Thor to a stalemate in Silver Surfer #88, but what makes this impressive is that during this battle the Asgardian's strength was actually being enhanced by the Power Gem. He was able to fight Odin to a standstill in Warlock and the Infinity Watch #25, shrugging off blasts from the All-Father and Silver Surfer simultaneously. In Thanos #11, he fought to a standstill against a Phoenix-Force powered Thane (his Inhuman son), even punching him through a planet, causing it to explode.
Thanos is clearly one of Marvel's strongest characters, but how does he stack up against the Jade Giant? Hulk is known for his raw physical strength, and for his ability to get stronger as he increases his adrenaline levels. One issue when trying to determine Hulk's strength level is that there are multiple different versions of the Hulk that Bruce Banner may turn into. There are currently six main Hulk personas, each with various base-level strengths.
The most popular iteration of the Hulk is the Savage Hulk, with his classic green skin and childlike mentality. Stronger than the Joe Fixit and Professor Hulk identities, Savage Hulk has been able to hold his own against powerful entities before, but the more interesting versions would be Green Scar and Devil Hulk. Devil Hulk is much smarter than Savage Hulk, and is able to regenerate himself after being dismembered, but what is interesting about him is his connection to the Below-Place, a mystical hell that grants him the potential for greater strength. Green Scar (the Hulk that featured in both World War Hulk and Planet Hulk) is not only more intelligent and skilled in combat than Savage Hulk, but he is also the version of the Hulk at his angriest, and is the only one to really tap into the Hulk's real power.
Hulk also has had some impressive feats. Hulk once lifted a mountain weighing 150 billion tons during the events of the original Secret Wars crossover, and has also obliterated an asteroid twice the size of Earth with one hit in Marvel Presents #52. Devil Hulk has been shown to be able to defeat all of the Avengers at once, fracturing Thor's skull and overloading Black Panther's Panther Habit (the feature of his suit that allows it to store kinetic energy for redirection.) Green Scar was powerful enough to defeat the Avengers, Fantastic Four, and X-Men, and fought the Sentry until they both burned out (Sentry is a character described as having the power of a million exploding suns.) Green Scar's most impressive feat was reaching a state of anger where he became the World-Breaker, who could sink the eastern seaboard with just a few footsteps.
In past conflicts between the two, Thanos has been able to triumph, usually due to either having the Infinity Gauntlet, or using his control over cosmic energy to overpower the Hulk. In a conflict of purely physical strength, though, Hulk may present more of a challenge to the Mad Titan. While in the base Savage form, Thanos would likely still be able to gain a victory, though the longer the conflict lasts, and the more time Hulk has to get stronger, the lower the chances Thanos has of succeeding.
Devil Hulk would certainly put up more of a challenge than his Savage counterpart, and is impossible to truly kill, but Devil Hulk hasn't really gone up against the same tier of opponents Thanos has, so it seems likely the Mad Titan could still pull through. If Thanos were to be pitted against the World-Breaker Hulk, though, it seems the tables would be turned on the Eternal. While Thanos has been shown able to destroy planetary objects in conflict, W0rld-Breaker Hulk could sink a continent just by the act of walking. It seems unlikely that Thanos could best the World-Breaker without having access to the Infinity Gems, or some other kind of cosmic power boost/reality manipulation device. While Thanos surely lives up to his reputation as a scourge of the universe, and could likely defeat the Hulk in a chance encounter, the Mad Titan's maximum strength pales in comparison to the heights of destruction Bruce Banner's transformed self can reach.
