The admin User:Mesektet specifically said Mario is an outright hero and not pure of heart. Outright heroes cannot be pure of heart as well. If it makes you feel any better, I used to overdo the Complete Monster category on Villains Wikia. I was warned once by a regular user and ever since I was warned by an admin, I stopped. You also didn't explain how these characters are pure of heart besides adding them as such as well.