Merciful Heroes are very forgiving to others and are reluctant to kill, including villains that have wronged them in the past. Examples of this are with Batman from the DC Comics who is willing to go out there way as a Vigilante in Gotham but would not kill any criminals with the only exceptions of different adaptations of him through other various re-imaginings that contradict against the moral agency. This understandably can backfire on them at times, as they refuse to accept that there is no other option to kill sometimes, though some are willing to resort to killing when absolutely necessary. They are also the opposite of Sadists and the good counterpart of Corrupting Influences.

For obvious reasons, merciful heroes are rarely lethal.

Plenty of these types of Heroes can count as Pure Good so as long as they have their moral agency understanding between the sides of right and wrong.