Stainless Steve is a dark brown cyborg. The only remaining human part is his lower face. Apparently, he was an actor that appeared on several TV shows at one point. However, he was eventually fired because of his poor skills. As a result, he desperately joined Serious Sam in his fight against Mental.
Stainless Steve, along with Kleer Kenny, is a popular character to use in Deathmatch and other versus modes because he is harder to see when compared with the rest of the other characters.