If you mean not in comic books or video games there still are some pretty "tough" characters, or powerful ones. What about Q from Star Trek? Or some alien beings from Dr. Who. But you specifically mean beings who are "normal", as in no special powers. Just pointing out there isn't any agreed on definition on what is normal. Nikola Tesla was a real person but he would actually fit into the category of fiction well because of all the crazy things he invented; if you included reality I'd say he was the most powerful character, because he could really screw people up with his death day and Earth quake device. 🙂 May I also mention Luke Skywalker who isn't technically a comic and video game character? Ok so you specifically mean tough guy, in which case I'm not sure. Master Chief maybe? But doesn't be have some enhancement?