Is there a limit..?
...to the amount of crap the hero can take from a villain before finally snapping and killing him? Rank the following characters.
Batman
Spider-man
Superman
Captain Marvel
Flash
Which ones can be driven to the point where they cross the line and in which order they will break their "no killing" rule? No mindcontrol or blackmailing etc allowed. The hero must make the decision willingly because he's had enough.
Feel free to add your characters.