Drummer (in the TV show*) and Amos (in the TV show and books) from the The Expanse are great examples of what tough people are actually like in real life. Of course there is a bit more drama than is found in the world, but they both feel real.

And tough people are usually a bit dysfunctional or weird or misfits because of how you get tough.

Of course it helps that both Cara Gee and Wes Chatham did just such an excellent job of portraying their respective characters.

*In the books, Drummer is not so distinctive and does not have such a large role; the TV series much improves on this aspect.