Last of a kind
The protagonist is one of the last or the last representative of a kind.
The first video game about Last of a kind was released on December 2, 1994.
If this is a profession, then they usually do not bother spreading that profession about before they deal with the local evil overlord even if then. Likely with intending that they will be the last that's even needed, which is very bad in long term (unless the profession is part of the cause). Alternatively, the protagonist is one of the last remaining members of a species that is too few in number to repopulate and science (that they have at hand) has no solutions for it.