Marvel differentiate their superheroes from the more mythical, unrealistic figures of DC Comics by making their characters all too human. They are flawed, complex individuals who don't live by strict moral codes like Batman or Superman, instead doing their best to get a difficult job done. Which is why they're so open to killing people left, right and centre. Again, we're not sure that Loki or the race of alien Chitauri he employs to invade Earth actually kill anyone - the trickster god's slaughter of Agent Coulson got undone, so that doesn't count - but they do cause a bit of a mess in New York. You know who does kill people? The Avengers. The Avengers kill so many people. To be fair to Hawkeye and Black Widow, they're trained by SHIELD to be government assassins - it's kind of their bag. They've probably killed loads of people before, so sticking it to a bunch of ugly aliens is no skin off their nose. Which is why the former can be flinging arrows in the heads of the Chitauri and Black Widow can stab them in the spine and use it to commandeer one of those Flash Gordon floating scooters they pilot. Isn't that kind of messed up, though? So far as we can tell, the Chitauri don't actually hurt anyone. Again, ironically, that's thanks to the intervention of the Avengers; they heroically save civilians, whilst murdering a load of alien invaders in cold blood. That big armoured space whale that turns up was probably a sentient being, too, which doesn't stop the Hulk from tearing it apart and Thor frying it with some of his lightning. Then Iron Man explodes the remaining Chitauri - that's mass genocide in our book. Yeesh. And these are supposed to be the heroes?
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/