Bruno S is one of the actors Werner Herzog used in several of his films - both The Mystery of Kaspar Hauser and Stroszek. He's not a handsome man. He's never portrayed as clever - both Kaspar Hauser and Bruno Stroszek are simpletons in different ways - though it's interesting to note that both are made simple by upbringing, abuse and neglect, not born that way. In his real life, Bruno was the son of a prostitute; accounts say he was unwanted and we can imagine probably any number of reasons why. Anyhow, he was beaten so severely by his mother at age 3 that he became temporarily deaf. This led to his placement in a mental institution; he spent the next 23 years in various institutions, and in trouble with the law, a past shared by the character Bruno Stroszek. He was, after all that, truly certifiable - a schizophrenic.
Perhaps despite this past, he became a self-taught painter and musician, as can be seen in Stroszek when he plays his accordion and piano. He worked odd jobs - the kind you'd expect a marginal schizophrenic to do - and then Herzog saw him in a documentary on street musicians and was apparently charmed. This led to his major roles in Every Man for Himself and God Against All (1974) and Stroszek (1977) in which he could charm the world (or maybe just me).
He was very difficult to work with, though, sometimes needing several hours of screaming before he could do a scene, and ranting endlessly, a practice that Herzog humored, almost encouraged, forced the crew to work with (and listen to). Perhaps it is testament to Herzog that he could (or did he prefer to?) work with difficult actors like Bruno and Kinski and pull from them riveting and troubling characters in beautiful films. I find Bruno S to be one of the realest actors i can think of, and prefer him (in a movie) to almost any hunk you can name. Try me.