merchant selling things to cannoneer?

i just get the new jobs, and a merchant appear and said something about selling good stuff to us later. and he will be appear somewhere in the weapon shop

i just look around the whole world but just cant find him...

anyone know what is it about?
where is he??

thank you

Check the inn at Crescent Island.

he's in Bal Castle too, by the item shop.

Yeah, he can appear in a whole bunch of random locations. Just stop by an item shop or inn and see if he is there.