While the welcomed into the ranks of the Avengers, Defenders, and even S.H.I.E.L.D. However, part of what allows Hulk to be forgiven for the massive destruction he causes is the shockingly small death toll of his frequent rampages. In fact, according to Marvel lore, Hulk has never directly killed an innocent, whether battling the military or tearing down Avengers tower. As bizarre as this may seem, one hidden superpower explains how it's possible.
Up until the introduction of this power, Marvel's heroes generally considered themselves lucky that when the Hulk loses control, one or more of them are able to step in and save the lives he puts at risk. Indeed, Bruce Banner's perpetual nemesis General 'Thunderbolt' Ross often patted himself on the back for engaging Hulk before lives could be lost. However, they all missed a hidden power discerned by Amadeus Cho, the much-touted 'seventh-smartest man in the world.'
Having studied the Hulk after being rescued by him, Amadeus reveals his theory in The Incredible Hulk #110, by Greg Pak, Carlo Pagulayan, Jeffrey Huet, Chris Sotomayer, and Joe Caramagna - part of the World War Hulk event, in which Hulk claimed dominion over New York City. Threatened by Hulk when he tries to help the Green Goliath, Amadeus reveals that in all the s of Hulk's 'wild' rampages, there is no evidence that innocent lives were lost. Having read "every document about [Hulk] in every government database imaginable" and studied "every recording and report of every fight" he's ever been in, Amadeus believes that Bruce Banner is so smart that he can calculate the trajectories and consequences of physical actions. In short, while Bruce Banner is 'asleep' while Hulk is free, his super-genius mind is still part of the beast, plotting out every move so that no-one is killed.
It's important to note that this ability isn't foolproof. Hulk names several times when he's taken lives in the past, seemingly disproving this theory. However, Amadeus notes that they were either deadly enemies he killed knowingly, or else his mind was being controlled by an outside force, saying, "As long as your brain hasn't been tampered with, there's a part of you that's always running the numbers. You know where the innocents are and how to save them." The theory is bolstered by the fact that Amadeus himself is smart enough to have this ability on the small scale, 'seeing' trajectories in a way that allows him to perform small actions that end up having far larger consequences.
Of course, Amadeus is also a teenage boy, and so his perspective doesn't take into the ways in which Hulk's rampages still hurt people. Al Ewing and Joe Bennett's Immortal Hulk run seemingly confirms that the Savage Hulk identity has never taken an innocent life while also acknowledging that his rampages have destroyed homes and caused life-altering stress that undoubtedly harmed his victims' health in the long run. However, when it comes to clashing with Juggernaut in populated areas or swatting army helicopters out of the sky, Hulk has officially racked up 0 innocent casualties, and Amadeus' reasoning is the best explanation why.
Out of control as he may appear, the Hulk is an expression of Bruce Banner's rage and fear, so it makes sense he's able to tap into the genius scientist's mind to make sure no-one is unintentionally hurt. Marvel has wisely left the final word on this very specific type of super-intelligence to fans, but it's the best explanation yet for Hulk's lack of a body count, and emphasizes his bond to Bruce Banner not as a wholly separate being, but as a 'system' expressed through multiple persona, each with different strengths and weaknesses.
