These are heroes who are a friend of a villain. The source of the confrontation might vary, maybe their friend is possessed/brainwashed, maybe both still care for each-other but just have differences that are philosophical, maybe they consider each-other worthy adversaries, probably one has been good at all times and the other always evil but they enjoy each-other's company despite their difference, or probably they were once friends before they became enemies but with the hero holding out hope they can be again. When the two actually come to blows it is frequently centered as a big fight for both parties. These are such heroes, protagonists who have to fight those near and dear to them, whether such friendships can be maintained despite of the fight or if the villain can be redeemed. Pure of Heart heroes can quality as a friend of a villains as long as they are a true friend of a villain.