Aaaaannnd a question from a small child.
If this question was asked by an adult, I'm going to go right ahead and assume they don't expect me to do a thorough breakdown of all possible candidates here. It would take up nearly the rest of my life, and I still haven't watched the new season of Orange is the New Black.
The answer is Batman. Always was, always will be. Nothing beats the Bat. He's got a great origin, his go-to powers are stealth and fear, he's a scientist and a detective, he's got all the resources he could ever need and he's completely committed to helping people and making the world a better place. Also, he serves the ideal role of something fantastical in literature by playing a perfect metaphor for humanity, arguably by being a little on the nose as Batman doesn't have any super powers at all. He's just a person.
The best person ever.
I don't feel the need to go further. Everyone fucking loves Batman and much has been written on the subject. If you need any more convincing, look into all the iconic stories that have included Batman, or the depth of his rogue's gallery, or the impact he's had on pop culture in aggregate.
Everyone knows who Batman is. And if he was real, and in your city, you'd think twice about being a criminal for fear of meeting him in a dark alley.
Or you'd just do your crimes in a bright area that Batman would never appear in.
Short Answer: Did I just ruin Batman? Oops.