Some posted in ALL CAPS, retweeted WTF gifs and swore off Marvel when Captain America declared his allegiance to Hydra. A popular complaint was Cap turning bad, let alone joining the thinly-veiled Nazi equivalent Hydra went against everything Marvel. But making heroes villains is very much a part of the fabric of Marvel Comics. That’s been a Marvel writer staple and Cap probably won’t be the last big name hero to join the dark side.
Granted, most of them probably won’t go as hardcore as Captain America has in Secret Empire and ordering public executions for former allies, but you never know.
Without much effort I was able to come up a list of 14 other heroes who acted or became full-fledged villains. In some rare cases, it actually makes the character better. In most instances, it’s just a quick sales gimmick to drum up interest and get some big headlines. I’ll let you decided which heroes fall into what category.