Here we have some words that you won't learn by reading any grammar book. Be careful because this expression can be used only in informal conversation.
fulano: desconocido. En otras zonas es referente a desconocidos... Por ejemplo: Quien toco la puerta? , -- Nadie, un fulano que vende libros. o Puede ud. decirnos como sucedio todo? R= Si, para comenzar se acercaron dos fulanos a preguntar la hora.
It is not usually used as an insult, at least in its masculine form "fulano", it's used describe someone whose name you cannot remember or someone not very important. It may be a bit despective.Its equivalent in english would be <em>So-and-so</em>
You also use fulano when you dont know the name of that person or to put examples like imagine a situacion with a persons who is imaginary and if you dont have in mind any name you say fulano its despective or not depending the way or the meaning you give
