I feel like Ruben could possibly have some sort of relationship with the Fixers, given that he is a quite talented tinkerer and would probably have needed them in order to get parts for his leg. They probably won't be friends, or even act as if they actually like each other, but they would have a professional sort of relationship.  His power is the kind that he doesn't really need to hide, since it's not something he can use for anything but outright battle situations.