Joseph "Joe" Kendo' is the brother of deceased Gun Shop owner; Robert Kendo. He helped his brother customize special requested guns for his shop, and also served as a weapons instructor for S.T.A.R.S.
He is most known for finalizing the Beretta 92F S.T.A.R.S. Special, which he named the "Samurai Edge."
It is probable that Joseph lived out of the limits of Raccoon City, as the handgun that Leon starts with in RE4 is engraved "Kendo Custom Shop," similarly to the Samurai Edge. They are not easily seen in-game, but the engravings can be made out in the Bradygames walkthrough interior cover art and in the ARMS Magazine BioHazard 4 special.