Who would be the scariest is the question being posed here, not who would be the most powerful. It's a challenging question. However, I believe I would have to choose Captain America. I can imagine you shaking your head at me. How is Cap a more terrifying antagonist than, say, the Hulk, Doctor Strange, or Scarlet Witch? That's easy. Captain America is the character I chose since he is the least corruptible. Consider this. The other Avengers members are amply demonstrated to be humanly fallible: Who knows what sort of things Black Widow did while she worked against SHIELD. After losing his family, Hawkeye turned into a ronin who slaughtered criminals with shocking brutality. Iron Man, who has occasionally shown himself to be incredibly egotistical and conceited, he also created Ultron. If Hulk is not restrained, he becomes a monster. As a result of his disobedience and arrogance, Thor has a tendency to brag and has spent a good deal of time being unworthy. Captain America not so...