Then you are of no further interest to me, rivel... though I suspect your dreams will be filled with dark imaginings of the hedonistic pleasures you have denied yourself.
Unlike so-called basic emotions such as sadness, fear, and anger, guilt emerges a little later, in conjunction with a child's growing grasp of social and moral norms.
Personally, my money is on Tony Stark or Captain America biting the dust, because it's gotta be a character that the audience will be upset about. But who's it gonna be?